WO2017046896A1 - Nonaqueous electrolyte secondary battery and battery pack - Google Patents

Nonaqueous electrolyte secondary battery and battery pack Download PDF

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Publication number
WO2017046896A1
WO2017046896A1 PCT/JP2015/076312 JP2015076312W WO2017046896A1 WO 2017046896 A1 WO2017046896 A1 WO 2017046896A1 JP 2015076312 W JP2015076312 W JP 2015076312W WO 2017046896 A1 WO2017046896 A1 WO 2017046896A1
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Prior art keywords
negative electrode
current collector
mixture layer
electrode current
secondary battery
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PCT/JP2015/076312
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French (fr)
Japanese (ja)
Inventor
義之 五十崎
高見　則雄
圭吾 保科
充 石橋
泰伸 山下
Original Assignee
株式会社 東芝
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Application filed by 株式会社 東芝 filed Critical 株式会社 東芝
Priority to PCT/JP2015/076312 priority Critical patent/WO2017046896A1/en
Priority to JP2016510868A priority patent/JP6130052B1/en
Priority to CN201580072455.7A priority patent/CN107210425B/en
Priority to EP15904085.6A priority patent/EP3352253B1/en
Publication of WO2017046896A1 publication Critical patent/WO2017046896A1/en
Priority to US15/691,935 priority patent/US10326141B2/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/621—Binders
    • H01M4/622—Binders being polymers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L50/00—Electric propulsion with power supplied within the vehicle
    • B60L50/50—Electric propulsion with power supplied within the vehicle using propulsion power supplied by batteries or fuel cells
    • B60L50/60—Electric propulsion with power supplied within the vehicle using propulsion power supplied by batteries or fuel cells using power supplied by batteries
    • B60L50/64—Constructional details of batteries specially adapted for electric vehicles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L50/00—Electric propulsion with power supplied within the vehicle
    • B60L50/50—Electric propulsion with power supplied within the vehicle using propulsion power supplied by batteries or fuel cells
    • B60L50/60—Electric propulsion with power supplied within the vehicle using propulsion power supplied by batteries or fuel cells using power supplied by batteries
    • B60L50/66—Arrangements of batteries
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D133/00—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Coating compositions based on derivatives of such polymers
    • C09D133/02—Homopolymers or copolymers of acids; Metal or ammonium salts thereof
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    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D133/00—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Coating compositions based on derivatives of such polymers
    • C09D133/18—Homopolymers or copolymers of nitriles
    • C09D133/20—Homopolymers or copolymers of acrylonitrile
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
    • C09D5/24—Electrically-conducting paints
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    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J133/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Adhesives based on derivatives of such polymers
    • C09J133/18—Homopolymers or copolymers of nitriles
    • C09J133/20—Homopolymers or copolymers of acrylonitrile
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/20—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders
    • H01M50/204—Racks, modules or packs for multiple batteries or multiple cells
    • H01M50/207—Racks, modules or packs for multiple batteries or multiple cells characterised by their shape
    • H01M50/211—Racks, modules or packs for multiple batteries or multiple cells characterised by their shape adapted for pouch cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/20—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders
    • H01M50/296—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders characterised by terminals of battery packs
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/572—Means for preventing undesired use or discharge
    • H01M50/574—Devices or arrangements for the interruption of current
    • H01M50/581—Devices or arrangements for the interruption of current in response to temperature
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
    • C08K3/20—Oxides; Hydroxides
    • C08K3/22—Oxides; Hydroxides of metals
    • C08K2003/2237—Oxides; Hydroxides of metals of titanium
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2200/00—Safety devices for primary or secondary batteries
    • H01M2200/10—Temperature sensitive devices
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2220/00—Batteries for particular applications
    • H01M2220/20—Batteries in motive systems, e.g. vehicle, ship, plane
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/70—Energy storage systems for electromobility, e.g. batteries

Definitions

  • This embodiment relates to a non-aqueous electrolyte secondary battery and a battery pack.
  • lithium ion secondary batteries having a positive electrode containing LiCoO 2 or LiMn 2 O 4 as an active material and a negative electrode containing a carbonaceous material that occludes and releases lithium have been widely put into practical use for portable devices. Yes.
  • Such lithium ion secondary batteries have recently been developed from the viewpoint of environmental problems, such as electric vehicles (EV), hybrid vehicles (HEV), plug-in hybrid vehicles (plug-in hybrid vehicles). It is widely used as a power source for environmentally friendly vehicles such as electric vehicles (PHEV) and idling-stop systems (ISS).
  • a lithium ion secondary battery is mounted on a vehicle such as an electric vehicle or a hybrid vehicle, the lithium ion secondary battery is required to have storage performance in a high temperature environment, cycle performance, high output long-term reliability, and the like.
  • the lithium ion secondary battery when used in an engine room of an automobile as an alternative to a lead storage battery, the lithium ion secondary battery is required to have high temperature durability (for example, 80 ° C. or higher). Furthermore, when high performance is required in a cold region, high output performance and long life performance in a low temperature environment (for example, ⁇ 30 ° C.) are required.
  • the negative electrode used in the lithium ion secondary battery usually has a structure in which a negative electrode active material layer is formed on a current collector.
  • a negative electrode active material and a binder for binding the negative electrode active material and the current collector are used for the negative electrode active material layer.
  • a fluorine-based resin for example, polyvinylidene fluoride; PVdF
  • a fluorine-based resin for example, polyvinylidene fluoride; PVdF
  • fluorine-based resins and their modified products easily swell with respect to the electrolyte solution at high temperatures.
  • the high-temperature cycle performance may be deteriorated.
  • the network of electron conduction of the negative electrode is cut off with a charge / discharge cycle at a high temperature. Resistance rises.
  • An object of the embodiment is to provide a non-aqueous electrolyte secondary battery excellent in high temperature durability, a battery pack including the non-aqueous electrolyte secondary battery, and an automobile including the battery pack.
  • a non-aqueous electrolyte secondary battery includes a positive electrode, a negative electrode, and a non-aqueous electrolyte.
  • the negative electrode includes a negative electrode current collector and a negative electrode mixture layer disposed on the negative electrode current collector.
  • the negative electrode current collector includes a metal foil.
  • the negative electrode mixture layer contains a titanium-containing metal oxide that occludes and releases lithium ions and a binder containing an acrylic resin. This negative electrode satisfies the following formula (I).
  • ⁇ is the peel strength (N / m) between the current collector and the negative electrode mixture layer
  • ⁇ is the cutting strength (N / m) measured by the surface / interface cutting method in the negative electrode mixture layer. ).
  • FIG. 2 It is sectional drawing of the flat type nonaqueous electrolyte secondary battery which is an example of embodiment. It is an expanded sectional view of the A section of FIG. It is a schematic diagram of the flat type nonaqueous electrolyte secondary battery which is another example of embodiment. It is an expanded sectional view of the B section of FIG. It is a disassembled perspective view of the battery pack of embodiment. It is a block diagram which shows the electric circuit of the battery pack of FIG. 2 is a scanning electron microscope (scanSEM) image of a cross-section of a negative electrode in one example. It is a SEM image of the cross section of the negative electrode in one comparative example.
  • scanSEM scanning electron microscope
  • a non-aqueous electrolyte secondary battery includes a positive electrode, a negative electrode, and a non-aqueous electrolyte.
  • the negative electrode includes a negative electrode current collector including a metal foil, and a negative electrode mixture layer disposed on the negative electrode current collector and including a negative electrode active material and a binder.
  • the negative electrode active material contained in the negative electrode mixture layer contains a titanium-containing metal oxide that can occlude and release lithium ions.
  • the binder contains an acrylic resin.
  • the peel strength ⁇ (unit: N / m) between the negative electrode current collector and the negative electrode mixture layer and the cutting strength ⁇ (unit: N / m) measured by the surface / interface cutting method in the negative electrode mixture layer are: The relationship of ⁇ / ⁇ > 1.36 ⁇ 10 ⁇ 2 is satisfied.
  • FIG. 1 is a cross-sectional view of a flat type nonaqueous electrolyte secondary battery according to the first embodiment
  • FIG. 2 is an enlarged cross-sectional view of part A of FIG.
  • the flat wound electrode group 1 is housed in a bag-shaped exterior member 2 made of a laminate film having a metal layer interposed between two resin films.
  • the flat wound electrode group 1 is formed by winding a laminate in which the negative electrode 3, the separator 4, the positive electrode 5, and the separator 4 are laminated in this order from the outside, and then press-molding the laminate.
  • the outermost negative electrode 3 has a configuration in which a negative electrode mixture layer 3b containing a negative electrode active material is formed on one surface on the inner surface side of a negative electrode current collector 3a.
  • the negative electrode mixture layer 3b is formed on both surfaces of the electric body 3a.
  • the positive electrode 5 is configured by forming a positive electrode mixture layer 5b on both surfaces of a positive electrode current collector 5a.
  • the negative electrode terminal 6 is connected to the negative electrode current collector 3 a of the outermost negative electrode 3, and the positive electrode terminal 7 is connected to the positive electrode current collector 5 a of the inner positive electrode 5.
  • the negative electrode terminal 6 and the positive electrode terminal 7 are extended to the outside from the opening of the bag-shaped exterior member 2.
  • the liquid nonaqueous electrolyte is injected from the opening of the bag-shaped exterior member 2.
  • the wound electrode group 1 and the liquid nonaqueous electrolyte are completely sealed by heat-sealing the opening of the bag-shaped exterior member 2.
  • heat-sealing the negative electrode terminal 6 and the positive electrode terminal 7 are sandwiched by the bag-shaped exterior member 2 at this opening.
  • the non-aqueous electrolyte secondary battery according to the first embodiment is not limited to the configuration shown in FIGS. 1 and 2 described above, and can be configured as shown in FIGS. 3 and 4, for example.
  • FIG. 3 is a partially cutaway perspective view schematically showing another flat type nonaqueous electrolyte secondary battery according to the first embodiment
  • FIG. 4 is an enlarged cross-sectional view of a portion B in FIG. 3.
  • the laminated electrode group 11 is housed in an exterior member 12 made of a laminate film in which a metal layer is interposed between two resin films. As shown in FIG. 4, the stacked electrode group 11 has a structure in which positive electrodes 13 and negative electrodes 14 are alternately stacked with separators 15 interposed therebetween.
  • positive electrodes 13 each of which includes a positive electrode current collector 13 a and a positive electrode mixture layer 13 b supported on both surfaces of the positive electrode current collector 13 a.
  • the projecting end of the negative electrode current collector 14 a is electrically connected to the strip-shaped negative electrode terminal 16.
  • the tip of the strip-shaped negative electrode terminal 16 is drawn out from the exterior member 12 to the outside.
  • One end of the positive electrode 13a protruding from the negative electrode 14 is located on the opposite side to the one end of the negative electrode current collector 14a protruding.
  • One end of the positive electrode current collector 13 a protruding is electrically connected to the belt-like positive electrode terminal 17.
  • the tip of the strip-like positive electrode terminal 17 is located on the opposite side of the negative electrode terminal 16 and is drawn out from the side of the exterior member 12 to the outside.
  • a negative electrode used for a lithium ion secondary battery usually has a structure in which a negative electrode active material layer (negative electrode mixture layer) is formed on a current collector.
  • a negative electrode active material layer negative electrode mixture layer
  • a negative electrode active material and a binder for binding the negative electrode active material and the current collector are used in the negative electrode mixture layer.
  • the fluorine-based resin (for example, PVdF) that is a binder or a modified product thereof easily swells with respect to the electrolyte solution at high temperatures. Therefore, in a battery including a negative electrode using these as a binder, the network of electron conduction of the negative electrode is cut off with a charge / discharge cycle at a high temperature. As a result, the internal resistance of the negative electrode increases, leading to a decrease in the high-temperature cycle performance of the battery.
  • PVdF fluorine-based resin
  • acrylic resins are binders that are less likely to swell at high temperatures with respect to electrolyte solutions than fluororesins (such as PVdF) and their modified products.
  • fluororesins such as PVdF
  • a problem may occur when a negative electrode is produced.
  • the present inventors tried to produce a negative electrode using an acrylic resin as a binder the following problems occurred. Specifically, an acrylic resin as a binder, an active material, and carbon as a conductive material were dispersed in a dispersant (N-methyl-2-pyrrolidone) to prepare a slurry. This slurry was applied on an aluminum foil as a current collector.
  • a dispersant N-methyl-2-pyrrolidone
  • the negative electrode is composed of a titanium-containing metal oxide that absorbs and releases lithium ions and a negative electrode mixture layer that contains a binder, and the binder. Includes an acrylic resin.
  • the negative electrode current collector includes a metal foil.
  • the negative electrode included in the nonaqueous electrolyte secondary battery according to the embodiment includes a negative electrode current collector and a negative electrode mixture layer.
  • the negative electrode mixture layer includes a negative electrode active material, a conductive agent, and a binder.
  • the negative electrode mixture layer is formed on one side or both sides of the negative electrode current collector.
  • the negative electrode mixture layer is formed by applying a slurry containing the material of the negative electrode mixture layer on the negative electrode current collector.
  • the binder preferentially binds the active materials to each other.
  • the current collector and the mixture layer Adhesiveness may be reduced.
  • the negative electrode active material has priority over the binding between the negative electrode mixture layer and the negative electrode current collector. They are not bound together. Therefore, such a negative electrode is excellent in adhesion between the negative electrode mixture layer and the negative electrode current collector.
  • the peel strength ⁇ between the negative electrode current collector and the negative electrode mixture layer and the cutting strength ⁇ in the negative electrode mixture layer further satisfy the relationship of ⁇ / ⁇ ⁇ 4.9 ⁇ 10 ⁇ 2 . That is, the negative electrode preferably satisfies both the following formulas (I) and (II). ⁇ / ⁇ > 1.36 ⁇ 10 ⁇ 2 (I) ⁇ / ⁇ ⁇ 4.9 ⁇ 10 ⁇ 2 (II)
  • ⁇ is the peel strength (N / m) between the negative electrode current collector and the negative electrode mixture layer
  • ⁇ is the cutting strength (N / M) measured by the surface / interface cutting method in the negative electrode mixture layer. m).
  • the peel strength ⁇ between the negative electrode current collector and the negative electrode mixture layer is preferably 2.5 N / m or more and 27 N / m or less.
  • the peel strength ⁇ is less than 2.5 N / m, the adhesiveness with the current collector is insufficient, and there is a possibility of hindering the production of the negative electrode. Further, the negative electrode mixture layer is peeled off from the negative electrode current collector along with the charge / discharge cycle, whereby the resistance of the battery is increased and the cycle performance may be deteriorated.
  • the peel strength ⁇ exceeds 27 N / m, the negative electrode itself is hard and fragile. Also in this case, it is easy to cause trouble in battery production.
  • a more preferable range of the peel strength ⁇ between the current collector and the negative electrode mixture layer is 3.5 N / m or more and 10 N / m or less.
  • the cutting strength ⁇ in the negative electrode mixture layer measured by the surface / interface cutting method is preferably 180 N / m or more and 900 N / m or less.
  • the cutting strength ⁇ in the negative electrode mixture layer can correspond to the shearing force of the negative electrode mixture layer.
  • the cutting strength ⁇ is less than 180 N /, the strength of the negative electrode mixture layer may not be sufficient.
  • the cutting strength ⁇ exceeds 900 N / m the negative electrode mixture layer may not be able to withstand the expansion and contraction associated with the charging / discharging of the battery.
  • the cutting strength ⁇ is more preferably 600 N / m or less.
  • the negative electrode mixture layer includes a titanium-containing metal oxide that absorbs and releases lithium ions as a negative electrode active material.
  • M1 is at least one metal element selected from the group consisting of Cs, K, Sr, Ba and Ca
  • M2 is Zr, Sn, V, Ta, Mo, W, Fe, Co, Mn
  • Al orthorhombic Na-containing niobium tita Less selected from composite oxides can be used more than one.
  • the negative electrode mixture layer may include a conductive agent.
  • the conductive agent include carbonaceous materials such as graphite (graphite), acetylene black, carbon black, carbon nanofibers, and carbon nanotubes. These carbonaceous materials may be used alone or a plurality of carbonaceous materials may be used.
  • the binder includes an acrylic resin (acrylic polymer).
  • the acrylic resin may be a polymer or a copolymer.
  • the acrylic resin may contain both a polymer and a copolymer.
  • the acrylic resin does not easily swell with respect to the electrolyte solution at a high temperature, and the electron conduction network of the negative electrode is maintained even when the charge / discharge cycle is repeated at a high temperature. Therefore, in a battery including a negative electrode using an acrylic resin, an increase in cell resistance at a high temperature is suppressed, and the high temperature cycle performance of the battery is improved.
  • Examples of the monomer constituting the acrylic resin (acrylic polymer) include a monomer having an acrylic group and a monomer having a methacryl group.
  • the monomer having an acrylic group is typically acrylic acid or an acrylate ester.
  • the monomer having a methacryl group is typically methacrylic acid or a methacrylic ester.
  • Examples of monomers constituting the acrylic resin (acrylic polymer) include ethyl acrylate, methyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, isononyl acrylate, hydroxyethyl acrylate, methyl methacrylate, methacrylic acid Glycidyl, acrylonitrile, styrene, and acrylamide are included.
  • acrylic resin those mainly composed of an acrylic resin containing a nitrile group are preferable.
  • Specific examples include those mainly composed of polyacrylonitrile.
  • Such a binder has a particularly strong interaction with the titanium-containing metal oxide that is the negative electrode active material. This is presumably due to the strong interaction between the surface functional group (nitrile group) in the acrylic resin such as polyacrylonitrile and the surface of the titanium-containing metal oxide.
  • the above-described problems in producing the negative electrode are likely to occur. Therefore, when a binder mainly composed of an acrylic resin containing a nitrile group is used, it can be expected that a more remarkable effect can be expected by adopting the configuration of the embodiment.
  • binder two or more kinds of acrylic resins may be mixed and used. Moreover, you may contain 1 or more types of binders other than acrylic resin.
  • binders other than acrylic resins are polyvinylidene fluoride (PVdF), other fluororubbers, polypropylene (PP), polyethylene (polyethylene; PE), carboxymethyl cellulose (CMC). , Polyimide (PI), polyamidemide (PAI), and the like.
  • PVdF polyvinylidene fluoride
  • PP polypropylene
  • PE polyethylene
  • CMC carboxymethyl cellulose
  • PI polyimide
  • PAI polyamidemide
  • the ratio of the binder other than the acrylic resin is preferably 30% by weight or less of all the binders included in the negative electrode. More preferably, the ratio of the binder other than the acrylic resin is 10% by weight or less.
  • the compounding ratio of the negative electrode active material, the conductive agent and the binder is preferably as follows.
  • the compounding ratio of the negative electrode active material is preferably in the range of 70% by mass to 96% by mass.
  • the compounding ratio of the negative electrode conductive agent is preferably in the range of 2% by mass to 28% by mass.
  • the blending ratio of the binder is preferably in the range of 2% by mass to 28% by mass.
  • the conductive agent When the conductive agent is less than 2% by mass, the current collecting performance of the negative electrode mixture layer is lowered, and the large current performance of the nonaqueous electrolyte secondary battery may be lowered.
  • the binder when the binder is less than 2% by mass, the binding property between the negative electrode mixture layer and the negative electrode current collector is lowered, and as a result, the resistance is increased and the cycle performance may be lowered.
  • the conductive agent and the binder are each preferably 28% by mass or less.
  • the weight per unit area of the negative electrode mixture layer is preferably 10 g / m 2 or more and 160 g / m 2 or less.
  • the weight per unit area of the negative electrode mixture layer refers to the area of the negative electrode mixture layer per one side when the negative electrode mixture layer is applied to both surfaces of the negative electrode current collector.
  • Production of a negative electrode mixture layer having a weight per unit area of less than 10 g / m 2 is not suitable for a mass production process.
  • the weight per unit area of the negative electrode mixture layer exceeds 160 g / m 2 , the negative electrode production is likely to be hindered.
  • a more preferable range of the weight per unit area of the negative electrode mixture layer is 25 g / m 2 to 140 g / m 2 .
  • the negative electrode mixture layer disposed on the negative electrode current collector preferably has a thickness of 10 ⁇ m to 100 ⁇ m per side of the current collector. A more preferable thickness range is 15 ⁇ m or more and 75 ⁇ m or less.
  • a conductive foil can be used as the negative electrode current collector.
  • a current collector examples include a metal foil and an alloy foil. It is preferable to use an aluminum foil or an aluminum alloy foil as the negative electrode current collector.
  • the thickness of the aluminum foil and aluminum alloy foil is preferably 20 ⁇ m or less, and more preferably 15 ⁇ m or less. Thereby, it can reduce in weight, maintaining the intensity
  • the purity of the aluminum foil is preferably 99% by weight or more.
  • the aluminum alloy an alloy containing an element such as Mg, Zn, or Si is preferable. On the other hand, when a transition element such as Fe, Cu, Ni, or Cr is included, the content is preferably 1% by weight or less.
  • an undercoat layer is further formed on the surface of the negative electrode current collector.
  • a metal foil having an undercoat layer formed on the surface is used as a current collector, the wettability of the current collector surface with respect to the slurry for forming the negative electrode mixture layer is improved.
  • the adhesiveness of a negative electrode collector and a negative mix layer can further be improved. This is because it is possible to suppress the so-called repelling phenomenon that the slurry repels from the aluminum foil, and to prevent the peel strength between the current collector and the mixture layer from being lowered.
  • the undercoat layer on the surface of the current collector, the above-described problems during the production of the negative electrode can be better suppressed, thereby improving the adhesion between the negative electrode current collector and the negative electrode mixture layer. can do.
  • the binder is the active material as described above. There are cases where they are bound preferentially. This is expected to be due to the interaction between the active material surface and the surface functional group of the binder.
  • an undercoat layer is formed on the current collector surface, it is possible to avoid the binder being used preferentially for the binding between the active materials due to the interaction between the active material and the acrylic resin. Can do. Therefore, a negative electrode excellent in the adhesion between the current collector and the mixture layer can be produced with higher probability.
  • the undercoat layer formed on the surface of the negative electrode current collector preferably contains a carbon material, and the thickness per side of the current collector is preferably 2 ⁇ m or less.
  • the carbon material contained in the undercoat layer graphite (graphite), acetylene black, carbon black and the like can be used.
  • the undercoat layer may contain a resin.
  • the undercoat layer can contain a resin.
  • Resins contained in the undercoat layer include fluorine resins (such as PVdF), polyacrylic acid, acrylic resins, polyolefin resins, polyimide (PI), polyamide (polyamide), and polyamideimide (PAI). Etc.
  • an acrylic resin is preferable. This is because by including an acrylic resin in the undercoat layer, the affinity between the undercoat layer and the acrylic resin as the binder contained in the negative electrode mixture layer becomes excellent.
  • the negative electrode included in the nonaqueous electrolyte secondary battery according to the first embodiment can be produced by, for example, the following method. First, a negative electrode active material, a conductive agent, and a binder are suspended in a solvent to prepare a slurry. This slurry is applied to one side or both sides of the negative electrode current collector. Next, the applied slurry is dried to form a negative electrode mixture layer. Thereafter, the current collector and the negative electrode mixture layer are pressed.
  • the ratio ( ⁇ / ⁇ ) of the peel strength ⁇ and the cutting strength ⁇ in the negative electrode can be set to an appropriate value.
  • the peel strength ⁇ between the negative electrode mixture layer and the negative electrode current collector can naturally vary depending on the type of material such as the active material and binder used in the negative electrode mixture layer, but is also affected by the manufacturing conditions of the negative electrode.
  • a slurry containing a negative electrode active material, a conductive agent, and a binder is applied on the negative electrode current collector.
  • the slurry coating speed and the thickness of the coating film are applied.
  • the peel strength ⁇ can be increased.
  • peeling strength (alpha) may change also with the drying temperature at this time.
  • the cutting strength ⁇ can vary depending on the type of material such as an active material and a binder used for the negative electrode mixture layer, and is also affected by the manufacturing conditions of the negative electrode, similarly to the peel strength ⁇ .
  • the cutting strength ⁇ can vary depending on the thickness of the slurry applied on the negative electrode current collector. As will be described later, in the production of the negative electrode, the current collector and the negative electrode mixture layer formed thereon are pressed, and the cutting strength ⁇ depends on the pressing temperature at this time, that is, the temperature of the roll used in the pressing. Can change.
  • a coating material is prepared by mixing a carbon material such as graphite or acetylene black in a solution obtained by dissolving the above-described resin in a solvent.
  • a current collector having an undercoat layer formed on the surface can be produced by applying this paint on an aluminum foil serving as a current collector and then drying the paint.
  • a slurry containing a negative electrode active material, a conductive agent and a binder was applied to the surface (one side or both sides) on which the undercoat layer was formed, and the negative electrode was formed in the same manner as described above. Can be produced.
  • the peel strength ⁇ between the current collector and the negative electrode mixture layer in the negative electrode can be measured using an electrode peel strength measuring device (rheometer).
  • the measurement method is as follows. First, a measurement sample is obtained by cutting a negative electrode to be tested into a 2 ⁇ 5 cm strip shape. Next, a tape is stuck on the surface of the negative electrode mixture layer of each measurement sample.
  • the tape used here for example, Scotch (registered trademark) double-sided tape 665 (winding core diameter: 25 mm) manufactured by 3M can be used.
  • the tape By applying the tape to an electrode peel strength measuring device, the negative electrode mixture layer is peeled from the negative electrode current collector at a peel angle of 180 ° and a peel rate of 2 cm / min.
  • the force required for peeling the negative electrode mixture layer is recorded, and converted to an appropriate unit to obtain the peel strength (N / m).
  • the conversion to an appropriate unit indicates that the conversion is performed so that the unit is the same as the cutting strength measured by the surface / interface cutting method described below.
  • the cutting strength ⁇ in the negative electrode mixture layer can be measured by a surface / interface cutting method.
  • the surface / interface cutting method uses a fine and sharp cutting blade, performs cutting in the horizontal direction while controlling the depth position of the blade with respect to the sample surface, and measures the stress applied to the blade.
  • the cutting strength in the negative electrode mixture layer can be measured by performing cutting while fixing the depth position of the blade to a predetermined depth in the negative electrode mixture layer. At this time, cutting is performed at a constant required speed in the length direction (horizontal direction) of the current collector. At that time, the cutting strength ⁇ (N / m) in the negative electrode mixture layer is obtained from the stress received by the tip of the cutting blade by cutting the inside of the negative electrode mixture layer.
  • the measurement of the cutting strength by the surface / interface cutting method can be performed by using a cutting strength measuring device such as a surface-and-interfacial-cutting-analysis system (SAICAS) (registered trademark).
  • SAICAS surface-and-interfacial-cutting-analysis system
  • the surface / interface cutting method may be referred to as the SAICAS method.
  • As the cutting blade a ceramic blade made of borazon material having a blade width of 1.0 mm is used.
  • the blade angle is a rake angle of 20 degrees and a bald angle of 10 degrees.
  • the blade is moved to a predetermined depth in the negative electrode mixture layer by cutting at a constant speed of 2 ⁇ m / second in horizontal speed and 0.2 ⁇ m / second in vertical speed.
  • cutting in the vertical direction is stopped, and cutting strength is measured in a constant speed mode with a horizontal speed of 2 ⁇ m / sec.
  • the measurement temperature is room temperature and the sample temperature is room temperature (25 ° C.).
  • the presence of acrylic resin as a binder in the negative electrode mixture layer is determined by infrared absorption spectrum (IR) analysis or pyrolysis-gas chromatography (mass / spectrometry; Py-). GC / MS).
  • the components of the binder in the negative electrode mixture layer can be confirmed by the following procedure.
  • a fully discharged battery is disassembled in a glove box filled with argon.
  • the completely discharged state means that the state of charge (SOC) is 0%.
  • the negative electrode to be measured is taken out from the disassembled battery.
  • This negative electrode is washed with a suitable solvent.
  • a solvent used for washing for example, ethyl methyl carbonate may be used.
  • NMP N-methyl-2-pyrrolidone
  • DMF dimethylformamide
  • IR measurement is performed on the remaining solid content by, for example, a reflection measurement method.
  • a reflection measurement method for example, FT / IR-6100 DTGS detector manufactured by JASCO Corporation can be used. By analyzing the data thus obtained, the presence of the acrylic resin in the negative electrode mixture layer can be confirmed.
  • the components of the binder in the negative electrode mixture layer can be confirmed by the following procedure.
  • the negative electrode is taken out from the decomposed battery and washed.
  • the negative electrode mixture layer is peeled off from the washed negative electrode using a spatula-like tool. At this time, care should be taken not to mix the negative electrode current collector.
  • the peeled mixture layer is set in a measurement holder and measured.
  • a stainless steel sample cup whose surface is subjected to an inert treatment is preferable.
  • the sample amount is preferably about 1 mg.
  • Py-GC / MS measuring device for example, Py (Pyrolyzer): PY-2020id manufactured by Frontier Laboratories, and GS / MS connected thereto: 7890GC / 5975CMSD manufactured by Agilent Technology Co., Ltd. may be used. it can.
  • an automatic sampler can be used to automatically drop a sample into the core of the thermal decomposition apparatus. In this case, it is preferable to measure at a thermal decomposition temperature of 600 ° C. Sample degradation occurs in a helium carrier gas stream at 50 ml / min and the product is introduced online into the GC / MS via a 50: 1 splitter.
  • the temperature of the interface unit connecting the pyrolyzer and the GC / MS and the sample introducing unit of the GC / MS are set to 320 ° C.
  • a nonpolar column for example, a separation column using a non-polar chemically bonded poly (5% phenyl) methylsiloxane as a stationary phase (film thickness: 0.25% ⁇ m) can be used.
  • the separated product is detected by a directly connected quadrupole mass spectrometer. The presence of the acrylic resin in the negative electrode mixture layer can be confirmed by analyzing the data thus obtained.
  • the presence or absence of an undercoat layer on the surface of the negative electrode current collector was confirmed by observing the cross section of the negative electrode with a scanning electron microscope (SEM) and elemental analysis (energy X-ray X-ray spectrocopy: EDX). can do.
  • SEM scanning electron microscope
  • elemental analysis energy X-ray X-ray spectrocopy: EDX. can do.
  • SOC 0% completely discharged state
  • the negative electrode including the undercoat layer to be measured is taken out from the decomposed battery.
  • This negative electrode is washed with a suitable solvent.
  • a solvent used for washing for example, ethyl methyl carbonate may be used. Insufficient cleaning may make it difficult to observe the undercoat layer due to the influence of lithium carbonate, lithium fluoride, etc. remaining in the negative electrode.
  • the cross section of the negative electrode taken out in this way is cut out with an ion milling device.
  • the cross section of the cut-out negative electrode is attached to the SEM sample stage.
  • treatment is performed using a conductive tape or the like so that the negative electrode does not peel off or float from the sample stage.
  • the negative electrode attached to the SEM sample stage is observed with a scanning electron microscope (SEM). It is preferable that the negative electrode be introduced into the sample chamber while maintaining the inert atmosphere during SEM measurement.
  • SEM scanning electron microscope
  • the positive electrode includes a positive electrode current collector and a positive electrode active material layer (positive electrode mixture layer).
  • the positive electrode mixture layer includes a positive electrode active material, a conductive agent, and a binder.
  • the positive electrode mixture layer is formed on one side or both sides of the positive electrode current collector.
  • manganese dioxide that absorbs lithium, iron oxide, copper oxide, nickel oxide, lithium manganese composite oxide (for example, Li x Mn 2 O 4 or Li x MnO 2 ), lithium nickel composite oxide (Eg, Li x NiO 2 ), lithium cobalt composite oxide (eg, Li x CoO 2 ), lithium nickel cobalt composite oxide (eg, LiNi 1-y Co y O 2 ), lithium manganese cobalt composite oxide ( For example, Li x Mn y Co 1- y O 2), lithium-nickel-cobalt-manganese composite oxide (e.g., LiNi 1-yz Co y Mn z O 2), lithium-nickel-cobalt-aluminum composite oxide (e.g., LiNi 1-yz Co y Al z O 2 ), lithium manganese nickel composite oxide having a spinel structure (eg, Li x Mn 2 -y Ni y O 4 ), lithium phosphonate, sodium x Mn 2 -y Ni
  • lithium manganese composite oxide Li x Mn 2 O 4
  • lithium cobalt composite oxide Li x CoO 2
  • lithium nickel cobalt composite oxide Li x Ni 1-y CoyO 2
  • lithium manganese cobalt composite oxide Li x Mn y Co 1- y O 2
  • lithium-nickel-cobalt-manganese composite oxide e.g., LiNi 1-yz Co y Mn z O 2
  • lithium phosphates having an olivine structure e.g., Li x FePO 4, Li x MnPO 4 , Li x Mn 1-y Fe y PO 4 , Li x CoPO 4
  • 0 ⁇ x ⁇ 1, 0 ⁇ y ⁇ 1, and 0 ⁇ z ⁇ 1 are preferable.
  • Examples of the conductive agent include carbonaceous materials such as acetylene black, carbon black, graphite, carbon nanofiber, and carbon nanotube. These carbonaceous materials may be used alone or a plurality of carbonaceous materials may be used.
  • the binder fills the gap between the dispersed positive electrode active materials, binds the positive electrode active material and the conductive agent, and binds the positive electrode active material and the positive electrode current collector.
  • binder examples include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), a modified polyvinylidene fluoride (PVdF), a polyimide (polyimide), and a polyamideimide (polyamideimide). PAI), acrylic resins (acrylic polymers) and the like.
  • PTFE polytetrafluoroethylene
  • PVdF polyvinylidene fluoride
  • PVdF modified polyvinylidene fluoride
  • PAI acrylic resins (acrylic polymers) and the like.
  • acrylic resins (acrylic polymers) are less likely to swell with respect to the electrolyte solution at high temperatures, and the electron conduction network of the positive electrode is maintained even after repeated charge / discharge cycles at high temperatures. Therefore, a battery including a positive electrode using an acrylic resin as a binder is preferable because an increase in cell resistance at high temperatures is suppressed and the high-temperature cycle performance of the battery is improved.
  • the acrylic resin may be a polymer or a copolymer.
  • the acrylic resin may contain both a polymer and a copolymer.
  • Examples of the monomer constituting the acrylic resin (acrylic polymer) include a monomer having an acrylic group and a monomer having a methacryl group.
  • the monomer having an acrylic group is typically acrylic acid or an acrylate ester.
  • the monomer having a methacryl group is typically methacrylic acid or a methacrylic ester.
  • Examples of monomers constituting the acrylic resin (acrylic polymer) include ethyl acrylate, methyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, isononyl acrylate, hydroxyethyl acrylate, methyl methacrylate, methacrylic acid Glycidyl, acrylonitrile, styrene, and acrylamide are included.
  • acrylic resin those mainly composed of an acrylic resin containing a nitrile group are preferable. Specific examples include those mainly composed of polyacrylonitrile.
  • binder two or more kinds of acrylic resins may be mixed and used.
  • binders other than acrylic resin may be included.
  • binders other than acrylic resins include polyvinylidene fluoride (PVdF), other fluororubbers, polypropylene (PP), polyethylene (PE), carboxymethyl cellulose (CMC). ), Polyimide (PI), polyamideimide (PAI), and the like.
  • the ratio of the binder other than the acrylic resin is preferably 30% by weight or less of all the binders included in the positive electrode. More preferably, it is 10 weight% or less.
  • the positive electrode active material, conductive agent and binder in the positive electrode layer are preferably blended in the following proportions.
  • the positive electrode active material is preferably blended at a ratio of 80% by mass to 95% by mass.
  • the conductive agent is preferably blended at a ratio of 3% by mass to 18% by mass.
  • the binder is preferably blended at a ratio of 2% by mass to 17% by mass.
  • Sufficient positive electrode strength can be obtained by setting the ratio of the binder to 2% by mass or more. By setting the ratio of the binder to 17% by mass or less, the blending amount of the binder serving as an insulating material in the positive electrode can be reduced, and the internal resistance of the positive electrode can be reduced.
  • the positive electrode current collector is preferably an aluminum foil or an aluminum alloy foil containing one or more elements selected from the group consisting of Mg, Zn and Si.
  • the thickness of the aluminum foil and the aluminum alloy foil is preferably 20 ⁇ m or less, and more preferably 15 ⁇ m or less.
  • the purity of the aluminum foil is preferably 99% by weight or more.
  • transition metals such as Fe, Cu, Ni, and Cr are contained, their content is preferably 1% by mass or less.
  • the density of the positive electrode mixture layer is preferably 3 g / cm 3 or more.
  • the positive electrode can be produced, for example, by the following method.
  • a positive electrode active material, a binder, and a conductive agent are suspended in a suitable solvent to prepare a slurry.
  • This slurry is applied to the surface of the positive electrode current collector.
  • the applied slurry is dried to form a positive electrode layer.
  • the positive electrode current collector and the positive electrode layer are pressed.
  • the organic solvent for dispersing the binder include N-methylpyrrolidone (NMP) and dimethylformamide (DMF).
  • NMP N-methylpyrrolidone
  • DMF dimethylformamide
  • the positive electrode may also be produced by forming a positive electrode active material, a binder and a conductive agent into a pellet to form a positive electrode layer, which is disposed on the positive electrode current collector.
  • Non-aqueous electrolytes include liquid organic electrolytes prepared by dissolving electrolytes in organic solvents, gelled organic electrolytes in which liquid organic solvents and polymer materials are combined, or lithium salt electrolytes and polymer materials And a solid non-aqueous electrolyte. Moreover, you may use the normal temperature molten salt (ionic melt) containing lithium ion as a non-aqueous electrolyte.
  • the polymer material include polyvinylidene fluoride (PVdF), polyacrylonitrile (PAN), polyethylene oxide (PEO), and the like.
  • the non-aqueous electrolyte is preferably liquid or gel, has a boiling point of 100 ° C. or higher, and contains an organic electrolyte or a room temperature molten salt.
  • a liquid organic electrolyte is prepared by dissolving an electrolyte in an organic solvent at a concentration of 0.5 to 2.5 mol / L. Thereby, a high output can be taken out even in a low temperature environment.
  • a more preferable range of the concentration of the electrolyte in the organic electrolyte is a range of 1.5 to 2.5 mol / L.
  • the liquid non-aqueous electrolyte may also be referred to as a non-aqueous electrolyte.
  • Examples of the electrolyte include lithium tetrafluoroborate (LiBF 4 ), lithium hexafluorophosphate (LiPF 6 ), lithium hexafluoroarsenide (LiAsF 6 ), lithium perchlorate (LiClO 4 ), and trifluoromethanesulfone.
  • Lithium oxide LiCF 3 SO 3
  • bistrifluoromethylsulfonylimide lithium LiN (CF 3 SO 2 ) 2
  • bispentafluoroethylsulfonylimide lithium LiN (C 2 F 5 SO 2 ) 2
  • tristrifluoromethyl examples thereof include lithium sulfonate (Li (CF 3 SO 2 ) 3 C), lithium oxalate difluoroborate (LiBF 2 C 2 O 4 ), lithium bisoxalate borate (LiB [(OCO) 2 ] 2 ), and the like.
  • the type of electrolyte can be one type or two or more types. Among these, those containing lithium hexafluorophosphate (LiPF 6 ) are preferable because they hardly oxidize even at a high potential.
  • organic solvent examples include cyclic carbonates such as propylene carbonate (PC) and ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), and methyl ethyl carbonate.
  • Chain carbonates such as (methyl ethyl carbonate (MEC)), chain ethers such as dimethoxyethane (DME) and diethoxyethane (DEE), tetrahydrofuran (THF), dioxolane (DOX) and the like
  • Examples include cyclic ether, ⁇ -butyrolactone (GBL), acetonitrile (AN), sulfolane (SL), and the like.
  • These organic solvents can be used alone or in the form of a mixture of two or more.
  • a non-aqueous solvent including a second solvent composed of at least one chain carbonate selected from the group consisting of dimethyl carbonate (DMC) has high stability at a high potential of 4.4 to 4.5V. Therefore, when such a nonaqueous solvent is used, the cycle life performance of the nonaqueous electrolyte secondary battery can be improved.
  • a nonaqueous solvent containing ethylene carbonate and diethyl carbonate is excellent in stability at a high potential of 4.4 to 4.5 V, and can suppress oxidative decomposition of the nonaqueous electrolyte.
  • the blending ratio of the second solvent is preferably 70% by volume or more.
  • the non-aqueous electrolyte can further include an additive.
  • an additive for example, vinylene carbonate (vinylene carbonate; VC), vinylene acetate (vinylene acetate; VA), vinylene butyrate, vinylene hexanate, vinylene crotonate, catechol carbonate, propane sultone, difluoro phosphorus
  • vinylene carbonate vinylene carbonate
  • VC vinylene carbonate
  • VA vinylene acetate
  • VA vinylene butyrate
  • vinylene hexanate vinylene crotonate
  • catechol carbonate propane sultone
  • difluoro phosphorus examples include lithium acid (LiPF 2 O 2 ).
  • lithium difluorophosphate LiPF 2 O 2
  • high temperature durability can be improved significantly.
  • the concentration of the additive is preferably in the range of 0.1% by mass to 3% by mass with respect to 100% by mass of the nonaqueous electrolyte.
  • a more preferable range of the concentration of the additive is 0.5% by mass or more and 2.5% by mass or less.
  • separator for example, a porous film formed from a material such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), cellulose, and polyvinylidene fluoride (PVdF), synthetic A resin nonwoven fabric or the like can be used. Furthermore, the separator which apply
  • PE polyethylene
  • PP polypropylene
  • PET polyethylene terephthalate
  • PVdF polyvinylidene fluoride
  • Exterior material As the exterior member, a laminated film bag-like container or a metal container is used.
  • Examples of the shape include a flat type, a square type, a cylindrical type, a coin type, a button type, a sheet type, and a laminated type.
  • a large battery mounted on a two-wheel or four-wheel automobile or the like may be used.
  • the laminate film a multilayer film in which a metal layer is interposed between resin films is used.
  • the metal layer is preferably an aluminum foil or an aluminum alloy foil for weight reduction.
  • a polymer material such as polypropylene (PP), polyethylene (PE), nylon, and polyethylene terephthalate (PET) can be used.
  • the laminate film can be formed into the shape of an exterior member by sealing by heat sealing.
  • the laminate film preferably has a thickness of 0.2 mm or less.
  • the metal container can be formed from aluminum or an aluminum alloy.
  • the aluminum alloy preferably contains elements such as magnesium, zinc and silicon.
  • the content of transition metals such as iron, copper, nickel and chromium is preferably 100 ppm or less. Thereby, it becomes possible to dramatically improve long-term reliability and heat dissipation in a high temperature environment.
  • the metal container preferably has a thickness of 0.5 mm or less, and more preferably has a thickness of 0.2 mm or less.
  • the negative electrode terminal is formed of a material that is electrically stable and has conductivity in a range where the potential with respect to the lithium ion metal is 1.0 V or more and 3.0 V or less.
  • the negative electrode terminal is preferably formed from aluminum or an aluminum alloy containing an element such as Mg, Ti, Zn, Mn, Fe, Cu, and Si.
  • the negative electrode terminal is preferably formed from the same material as the negative electrode current collector in order to reduce the contact resistance with the negative electrode current collector.
  • a portion where the negative electrode mixture layer is not formed thereon can be used as a negative electrode current collecting tab.
  • a negative electrode terminal can be welded to the negative electrode current collecting tab.
  • the negative electrode terminal can be welded to the undercoat layer even if the undercoat layer is formed on the surface of the negative electrode current collector tab.
  • the portion where the undercoat layer is not formed may be used as a negative electrode current collecting tab, and the negative electrode terminal may be welded.
  • the positive electrode terminal is formed of a material that is electrically stable and has electrical conductivity in a range where the potential with respect to the lithium ion metal is 3.0 V or more and 4.5 V or less.
  • the positive electrode terminal is preferably formed from aluminum or an aluminum alloy containing elements such as Mg, Ti, Zn, Mn, Fe, Cu, and Si.
  • the positive electrode terminal is preferably formed of the same material as the positive electrode current collector in order to reduce contact resistance with the positive electrode current collector.
  • a nonaqueous electrolyte secondary battery includes a positive electrode, a negative electrode current collector made of a metal foil, a negative electrode containing a titanium-containing metal oxide that absorbs and releases lithium ions, and a binder, and a nonaqueous electrolyte And a non-aqueous electrolyte secondary battery.
  • the titanium-containing metal oxide and the binder constitute a negative electrode mixture layer disposed on the negative electrode current collector.
  • the binder includes an acrylic resin.
  • this nonaqueous electrolyte secondary battery has a negative electrode excellent in adhesion between the negative electrode current collector and the negative electrode mixture layer. Therefore, the nonaqueous electrolyte secondary battery is excellent in output performance and excellent in high temperature durability (cycle performance).
  • the battery pack according to the second embodiment has at least one non-aqueous electrolyte secondary battery (that is, a single battery) according to the first embodiment.
  • a non-aqueous electrolyte secondary battery that is, a single battery
  • the single cells are electrically connected in series, parallel, or a combination of series and parallel.
  • the plurality of single cells 21 are laminated so that the negative electrode terminal 6 and the positive electrode terminal 7 extending to the outside are aligned in the same direction, and are fastened with an adhesive tape 22 to constitute an assembled battery 23. These unit cells 21 are electrically connected to each other in series as shown in FIG.
  • the printed wiring board 24 is disposed to face the side surface of the unit cell 21 where the negative electrode terminal 6 and the positive electrode terminal 7 extend. As shown in FIG. 6, the printed wiring board 24 is mounted with a thermistor 25, a protection circuit 26, and a terminal 27 for energizing external devices. An insulating plate (not shown) is attached to the surface of the protection circuit board 24 facing the assembled battery 23 in order to avoid unnecessary connection with the wiring of the assembled battery 23.
  • the positive electrode side lead 28 is connected to the positive electrode terminal 7 located in the lowermost layer of the assembled battery 23, and the tip thereof is inserted into the positive electrode side connector 29 of the printed wiring board 24 and electrically connected thereto.
  • the negative electrode side lead 30 is connected to the negative electrode terminal 6 located in the uppermost layer of the assembled battery 23, and the tip thereof is inserted into the negative electrode side connector 31 of the printed wiring board 24 and electrically connected thereto.
  • These connectors 29 and 31 are connected to the protection circuit 26 through wirings 32 and 33 formed on the printed wiring board 24.
  • the thermistor 25 detects the temperature of the unit cell 21, and the detection signal is transmitted to the protection circuit 26.
  • the protection circuit 26 can cut off the plus side wiring 34a and the minus side wiring 34b between the protection circuit 26 and the energization terminal 27 to the external device under a predetermined condition.
  • the predetermined condition is, for example, when the temperature detected by the thermistor 25 is equal to or higher than a predetermined temperature.
  • the predetermined condition is when the overcharge, overdischarge, overcurrent, etc. of the cell 21 are detected. This detection of overcharge or the like is performed for each single cell 21 or the entire single cell 21.
  • the battery voltage may be detected, or the positive electrode potential or the negative electrode potential may be detected.
  • a lithium electrode used as a reference electrode is inserted into each unit cell 21.
  • a wiring 35 for voltage detection is connected to each single cell 21, and a detection signal is transmitted to the protection circuit 26 through these wirings 35.
  • Protective sheets 36 made of rubber or resin are respectively disposed on the three side surfaces of the assembled battery 23. Specifically, the protective sheet 36 is disposed on three side surfaces of the assembled battery 23 other than the side surfaces from which the positive electrode terminal 7 and the negative electrode terminal 6 protrude.
  • the assembled battery 23 is stored in a storage container 37 together with each protective sheet 36 and the printed wiring board 24. That is, the protective sheet 36 is disposed on each of both inner side surfaces along the long side direction of the storage container 37 and one inner side surface along the short side direction.
  • the printed wiring board 24 is disposed on the inner surface on the opposite side of the protective sheet 36 disposed along the short side direction.
  • the assembled battery 23 is located in a space surrounded by the protective sheet 36 and the printed wiring board 24.
  • the lid 38 is attached to the upper surface of the storage container 37.
  • a heat shrink tape may be used for fixing the assembled battery 23.
  • protective sheets are arranged on both side surfaces of the assembled battery, the heat shrinkable tape is circulated, and then the heat shrinkable tape is heat shrunk to bind the assembled battery.
  • 5 and 6 show a configuration in which the cells 21 are connected in series, but in order to increase the battery capacity, they may be connected in parallel.
  • the assembled battery packs can be connected in series or in parallel.
  • the aspect of a battery pack is changed suitably according to a use.
  • a use of the battery pack according to the embodiment one that is required to exhibit excellent cycle performance when a large current is taken out is preferable.
  • Specific examples include a power source for a digital camera, a vehicle for a two- to four-wheel hybrid electric vehicle, a two- to four-wheel electric vehicle, an assist bicycle, and the like.
  • a battery pack using a nonaqueous electrolyte secondary battery excellent in high temperature durability is suitably used for in-vehicle use.
  • the battery pack according to the second embodiment includes a non-aqueous electrolyte secondary battery having excellent high-temperature durability, it can be suitably used even when placed in the engine room of an automobile.
  • a battery pack can be provided.
  • the battery pack according to the embodiment includes at least one nonaqueous electrolyte secondary battery according to the first embodiment.
  • Such a battery pack can exhibit high output and high durability at high temperatures.
  • Example 1 A non-aqueous electrolyte secondary battery similar to the non-aqueous electrolyte secondary battery shown in FIGS. 1 and 2 was produced by the following procedure.
  • lithium titanate (Li) having a spinel structure with a lithium occlusion / release potential of 2 V to 1.3 V (vs. Li / Li + ) with respect to the electrode potential of lithium metal and an average primary particle size of 0.8 ⁇ m. 4 Ti 5 O 12) were prepared particles.
  • this lithium titanate 90% by weight of this lithium titanate, 5% by weight of acetylene black as a conductive agent, 5% by weight of polyacrylonitrile as a binder, and a solid content ratio of 70% by weight of N-methylpyrrolidone (NMP) It added so that it might become.
  • NMP N-methylpyrrolidone
  • the slurry was wet pulverized and dispersed using a continuous bead mill (RMH-03, manufactured by IMEX Co., Ltd.) under the conditions of a rotational speed of 1500 rpm and a flow rate of 30 cc / min to prepare a slurry.
  • a continuous bead mill manufactured by IMEX Co., Ltd.
  • a negative electrode current collector which is an aluminum foil having a thickness of 15 ⁇ m and an undercoat layer (carbon resin layer) having a thickness of 1 ⁇ m formed on both surfaces. It was applied at a coating speed of 0.75 m / min using a construction apparatus (manufactured by Yurai Seiki Co., Ltd.) and dried at a drying temperature of 140 ° C. At this time, a portion of the negative electrode current collector where the slurry was not applied was left on the surface.
  • the obtained coated electrode was pressed at a pressing temperature of 25 ° C. by a roll press apparatus (manufactured by Ohno Roll), and a negative electrode mixture layer having a thickness of 20 ⁇ m per side and an electrode density of 2.0 g / cm 3 was obtained. It formed on the negative electrode collector.
  • a portion where the negative electrode mixture layer was not formed on the surface was punched into a band shape to form a negative electrode current collecting tab. In this way, a negative electrode was produced.
  • nickel cobalt lithium manganate (LiNi 0.34 Co 0.33 Mn 0.33 O 2 ) particles having a center particle diameter of 7.5 ⁇ m were prepared. 90% by weight of this nickel cobalt lithium manganate, 3% and 2% by weight of acetylene black and graphite powder as a conductive agent, and 5% by weight of polyacrylic acid (average molecular weight 450,000) as a binder, respectively. Then, the slurry was prepared by dispersing in N-methylpyrrolidone (NMP) solvent. The slurry was applied to both surfaces of a positive electrode current collector having a thickness of 15 ⁇ m, which was an aluminum foil. At this time, a portion where the slurry was not applied on the surface was left on the positive electrode current collector.
  • NMP N-methylpyrrolidone
  • the applied slurry was dried and pressed to form a positive electrode mixture layer having an electrode density of 3.2 g / cm 3 on the positive electrode current collector.
  • the weight of the positive electrode was adjusted to be 1.1 times the weight of the negative electrode.
  • a portion where the positive electrode mixture layer was not formed on the surface was punched into a band shape to form a positive electrode current collector tab. In this way, a positive electrode was produced.
  • Electrode group A positive electrode, a nonwoven fabric separator having a thickness of 20 ⁇ m, a negative electrode and a separator were laminated in this order, and then wound in a spiral shape. This was heated and pressed at 90 ° C. to produce a flat electrode group having a width of 30 mm and a thickness of 3.0 mm. The obtained electrode group was housed in a pack made of a laminate film and vacuum dried at 80 ° C. for 24 hours. As the laminate film, one having a polypropylene layer formed on both sides of an aluminum foil having a thickness of 40 ⁇ m and having an overall thickness of 0.1 mm was used.
  • nonaqueous electrolyte secondary battery A liquid non-aqueous electrolyte was poured into a laminate film pack containing the electrode group. Thereafter, the pack was completely sealed by heat sealing, and a non-aqueous electrolyte secondary battery (design capacity 1 Ah) having the structure shown in FIG. 1 and having a width of 35 mm, a thickness of 3.5 mm, and a height of 65 mm was produced. . This was designated as the secondary battery of Example 1.
  • Table 1 summarizes the negative electrode active material and binder used in the production of the negative electrode and the positive electrode active material used in the production of the positive electrode in Example 1 and Examples 2 to 13 below.
  • Table 2 summarizes the presence and thickness of the undercoat layer in the negative electrode current collector.
  • Table 3 summarizes the conditions for producing the negative electrodes (slurry coating speed, slurry drying temperature, press temperature) in Examples 1 to 13.
  • Table 3 shows the peel strength ⁇ between the negative electrode current collector and the negative electrode mixture layer, the cutting strength ⁇ in the negative electrode mixture layer, and the ratio ( ⁇ / The value of ⁇ ) is further shown.
  • Example 2 A slurry was prepared in the same manner as in the preparation of the negative electrode in Example 1. Also, a negative electrode current collector similar to that used for the negative electrode of Example 1 was prepared. A negative electrode was produced in the same manner as in Example 1, except that the coating speed was 1.0 m / min when this slurry was applied to both surfaces of the negative electrode current collector.
  • a nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 1 except that this negative electrode was used. This was designated as the secondary battery of Example 2.
  • Example 3 A slurry was prepared in the same manner as in the preparation of the negative electrode in Example 1. Also, a negative electrode current collector similar to that used for the negative electrode of Example 1 was prepared. A negative electrode was produced in the same manner as in Example 1 except that when the slurry was applied to both surfaces of the negative electrode current collector, the coating speed was 1.5 m / min.
  • a nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 1 except that this negative electrode was used. This was designated as the secondary battery of Example 3.
  • Example 4 As the negative electrode active material, the same lithium titanate (Li 4 Ti 5 O 12 ) particles as those used in Example 1 were prepared.
  • a negative electrode was produced in the same manner as in Example 1 except that the coating speed when applying this to both surfaces of the negative electrode current collector was 1.0 m / min.
  • a nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 2 except that this negative electrode was used. This was designated as the secondary battery of Example 4.
  • Example 5 As the negative electrode active material, the same lithium titanate (Li 4 Ti 5 O 12 ) particles as those used in Example 1 were prepared. 90% by weight of this lithium titanate, 7% by weight of acetylene black as a conductive agent, and 3% by weight of polyacrylic acid (average molecular weight 450,000) as a binder were blended into an N-methylpyrrolidone (NMP) solvent. The slurry was prepared by dispersing.
  • NMP N-methylpyrrolidone
  • This slurry was applied to both surfaces of a negative electrode current collector, which was an aluminum foil having a thickness of 15 ⁇ m and an undercoat layer (carbon resin layer) having a thickness of 0.3 ⁇ m formed on both surfaces. At this time, a portion of the negative electrode current collector where the slurry was not applied was left on the surface.
  • the applied slurry was dried and pressed to form a negative electrode mixture layer having a thickness of 20 ⁇ m on one side and an electrode density of 2.0 g / cm 3 on the negative electrode current collector.
  • the coating speed, drying temperature, and press temperature at this time were performed under the conditions shown in Table 3.
  • a portion of the negative electrode current collector where the negative electrode layer was not formed on the surface was punched into a band shape to form a negative electrode current collector tab. In this way, a negative electrode was produced.
  • a nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 1 except that this negative electrode was used. This was designated as the secondary battery of Example 5.
  • Example 6 As the negative electrode active material, the same lithium titanate (Li 4 Ti 5 O 12 ) particles as those used in Example 1 were prepared. 90% by weight of this lithium titanate, 4.5% by weight of acetylene black as a conductive agent, and 5.5% by weight of polyacrylic acid (average molecular weight 450,000) as a binder were blended, and N-methylpyrrolidone ( The slurry was prepared by dispersing in NMP) solvent.
  • the slurry was applied to both surfaces of a negative electrode current collector, which is an aluminum foil having a thickness of 15 ⁇ m and an undercoat layer (carbon resin layer) having a thickness of 2 ⁇ m formed on both surfaces. At this time, a portion of the negative electrode current collector where the slurry was not applied was left on the surface.
  • a negative electrode current collector which is an aluminum foil having a thickness of 15 ⁇ m and an undercoat layer (carbon resin layer) having a thickness of 2 ⁇ m formed on both surfaces.
  • the applied slurry was dried and pressed to form a negative electrode mixture layer having a thickness of 20 ⁇ m on one side and an electrode density of 2.0 g / cm 3 on the negative electrode current collector.
  • the coating speed, drying temperature, and press temperature at this time were performed under the conditions shown in Table 3.
  • a portion of the negative electrode current collector where the negative electrode mixture layer was not formed on the surface was punched into a band shape to form a negative electrode current collector tab. In this way, a negative electrode was produced.
  • a nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 1 except that this negative electrode was used. This was designated as the secondary battery of Example 6.
  • Example 7 A slurry was prepared in the same manner as in the preparation of the negative electrode in Example 1. This slurry was applied to both surfaces of a negative electrode current collector which was an aluminum foil having a thickness of 15 ⁇ m and an undercoat layer (carbon resin layer) having a thickness of 0.3 ⁇ m formed on both surfaces. At this time, a portion of the negative electrode current collector where the slurry was not applied was left on the surface.
  • the applied slurry was dried and pressed to form a negative electrode mixture layer having a thickness of 20 ⁇ m on one side and an electrode density of 2.0 g / cm 3 on the negative electrode current collector.
  • the coating speed, drying temperature, and press temperature at this time were performed under the conditions shown in Table 3.
  • a portion of the negative electrode current collector where the negative electrode mixture layer was not formed on the surface was punched into a band shape to form a negative electrode current collector tab. In this way, a negative electrode was produced.
  • a nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 1 except that this negative electrode was used. This was designated as the secondary battery of Example 7.
  • Example 8 As the negative electrode active material, the same lithium titanate (Li 4 Ti 5 O 12 ) particles as those used in Example 1 were prepared. 90% by weight of this lithium titanate, 5% by weight of acetylene black as a conductive agent, and polyacrylonitrile and polyacrylic acid (average molecular weight of 3 million) as binders were blended by 3% by weight and 2% by weight, respectively. A slurry was prepared by dispersing in N-methylpyrrolidone (NMP) solvent.
  • NMP N-methylpyrrolidone
  • This slurry was applied to both surfaces of a negative electrode current collector, which was an aluminum foil having a thickness of 15 ⁇ m and an undercoat layer (carbon resin layer) having a thickness of 0.3 ⁇ m formed on both surfaces. At this time, a portion of the negative electrode current collector where the slurry was not applied was left on the surface.
  • the applied slurry was dried and pressed to form a negative electrode mixture layer having a thickness of 20 ⁇ m on one side and an electrode density of 2.0 g / cm 3 on the negative electrode current collector.
  • the coating speed, drying temperature, and press temperature at this time were performed under the conditions shown in Table 3.
  • a portion of the negative electrode current collector where the negative electrode mixture layer was not formed on the surface was punched into a band shape to form a negative electrode current collector tab. In this way, a negative electrode was produced.
  • a nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 1 except that this negative electrode was used. This was the secondary battery of Example 8.
  • Example 9 As the negative electrode active material, the same lithium titanate (Li 4 Ti 5 O 12 ) particles as those used in Example 1 were prepared. 90% by weight of this lithium titanate, 5% by weight of acetylene black as a conductive agent, and 5% by weight of polyacrylic acid (average molecular weight of 3 million) as a binder were blended into an N-methylpyrrolidone (NMP) solvent. The slurry was prepared by dispersing.
  • NMP N-methylpyrrolidone
  • the slurry was applied to both surfaces of a negative electrode current collector, which is an aluminum foil having a thickness of 15 ⁇ m and an undercoat layer (carbon resin layer) having a thickness of 2 ⁇ m formed on both surfaces. At this time, a portion of the negative electrode current collector where the slurry was not applied was left on the surface.
  • a negative electrode current collector which is an aluminum foil having a thickness of 15 ⁇ m and an undercoat layer (carbon resin layer) having a thickness of 2 ⁇ m formed on both surfaces.
  • the applied slurry was dried and pressed to form a negative electrode mixture layer having a thickness of 20 ⁇ m on one side and an electrode density of 2.0 g / cm 3 on the negative electrode current collector.
  • the coating speed, drying temperature, and press temperature at this time were performed under the conditions shown in Table 3.
  • a portion of the negative electrode current collector where the negative electrode mixture layer was not formed on the surface was punched into a band shape to form a negative electrode current collector tab. In this way, a negative electrode was produced.
  • a nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 1 except that this negative electrode was used. This was the secondary battery of Example 9.
  • Example 10 As the negative electrode active material, a monoclinic titanium composite oxide (TiO 2 ) having an average primary particle diameter of 2 ⁇ m was prepared. 90% by weight of this titanium composite oxide, 6% by weight of acetylene black as a conductive agent, and 3% by weight and 1% by weight of polyacrylonitrile and polyacrylic acid (average molecular weight 450,000) as binders, respectively.
  • the slurry was prepared by dispersing in N-methylpyrrolidone (NMP) solvent.
  • NMP N-methylpyrrolidone
  • This slurry was applied to both surfaces of a negative electrode current collector, which was an aluminum foil having a thickness of 15 ⁇ m and an undercoat layer (carbon resin layer) having a thickness of 0.3 ⁇ m formed on both surfaces. At this time, a portion of the negative electrode current collector where the slurry was not applied was left on the surface.
  • the applied slurry was dried and pressed to form a negative electrode mixture layer having a thickness of 19 ⁇ m on one side and an electrode density of 2.0 g / cm 3 on the negative electrode current collector.
  • the coating speed, drying temperature, and press temperature at this time were performed under the conditions shown in Table 3.
  • a portion of the negative electrode current collector where the negative electrode mixture layer was not formed on the surface was punched into a band shape to form a negative electrode current collector tab. In this way, a negative electrode was produced.
  • a nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 1 except that this negative electrode was used. This was the secondary battery of Example 10.
  • a niobium-containing titanium composite oxide (TiNb 2 O 7 ) having an average primary particle size of 1 ⁇ m was prepared. 90% by weight of this niobium-containing titanium composite oxide, 6% by weight of acetylene black as a conductive agent, and 3% by weight and 1% by weight of polyacrylonitrile and polyacrylic acid (average molecular weight 450,000) as binders, respectively.
  • a slurry was prepared by mixing and dispersing in an N-methylpyrrolidone (NMP) solvent.
  • NMP N-methylpyrrolidone
  • This slurry was applied to both surfaces of a negative electrode current collector, which was an aluminum foil having a thickness of 15 ⁇ m and an undercoat layer (carbon resin layer) having a thickness of 0.3 ⁇ m formed on both surfaces. At this time, a portion of the negative electrode current collector where the slurry was not applied was left on the surface.
  • the applied slurry was dried and pressed to form a negative electrode mixture layer having a thickness of 15 ⁇ m per side and an electrode density of 2.4 g / cm 3 on the negative electrode current collector.
  • the coating speed, drying temperature, and press temperature at this time were performed under the conditions shown in Table 3.
  • a portion of the negative electrode current collector where the negative electrode mixture layer was not formed on the surface was punched into a band shape to form a negative electrode current collector tab. In this way, a negative electrode was produced.
  • a nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 10 except that this negative electrode was used. This was the secondary battery of Example 11.
  • a sodium-containing titanium composite oxide (Li 2 Na 2 Ti 6 O 14 ) having an average primary particle size of 1 ⁇ m was prepared. 90% by weight of this sodium-containing titanium composite oxide, 6% by weight of acetylene black as a conductive agent, and 3% by weight and 1% by weight of polyacrylonitrile and polyacrylic acid (average molecular weight 450,000) as binders, respectively.
  • a slurry was prepared by mixing and dispersing in an N-methylpyrrolidone (NMP) solvent.
  • NMP N-methylpyrrolidone
  • This slurry was applied to both surfaces of a negative electrode current collector, which was an aluminum foil having a thickness of 15 ⁇ m and an undercoat layer (carbon resin layer) having a thickness of 0.3 ⁇ m formed on both surfaces. At this time, a portion of the negative electrode current collector where the slurry was not applied was left on the surface.
  • the applied slurry was dried and pressed to form a negative electrode mixture layer having a thickness of 20 ⁇ m on one side and an electrode density of 2.0 g / cm 3 on the negative electrode current collector.
  • the coating speed, drying temperature, and press temperature at this time were performed under the conditions shown in Table 3.
  • a portion of the negative electrode current collector where the negative electrode mixture layer was not formed on the surface was punched into a band shape to form a negative electrode current collector tab. In this way, a negative electrode was produced.
  • a nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 10 except that this negative electrode was used. This was the secondary battery of Example 12.
  • Example 13 A slurry was prepared in the same manner as in the preparation of the negative electrode in Example 1. Also, a negative electrode current collector similar to that used for the negative electrode of Example 1 was prepared. A negative electrode was produced in the same manner as in Example 1, except that the coating speed was 1.0 m / min when this slurry was applied to both surfaces of the negative electrode current collector.
  • lithium manganese iron phosphate (LiMn 0.8 Fe 0.2 PO 4 ) particles having a center particle diameter of 9 ⁇ m were prepared.
  • N-methylpyrrolidone (90% by weight of lithium iron manganese phosphate, 3% by weight and 2% by weight of acetylene black and graphite powder as a conductive agent, and 5% by weight of polyacrylonitrile as a binder, respectively) NMP) was dispersed in a solvent to prepare a slurry.
  • the slurry was applied to both surfaces of a positive electrode current collector having a thickness of 15 ⁇ m, which was an aluminum foil. At this time, a portion where the slurry was not applied on the surface was left on the positive electrode current collector.
  • the applied slurry was dried and pressed to form a positive electrode mixture layer having an electrode density of 2.0 g / cm 3 on the positive electrode current collector.
  • the weight of the positive electrode was adjusted to be 1.1 times the weight of the negative electrode.
  • a portion where the positive electrode mixture layer was not formed on the surface was punched into a band shape to form a positive electrode current collector tab. In this way, a positive electrode was produced.
  • a nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 1 except that this negative electrode and positive electrode were used. This was the secondary battery of Example 13.
  • Table 4 summarizes the negative electrode active material and the binder type used in the production of the negative electrode, and the positive electrode active material used in the production of the positive electrode.
  • Table 5 summarizes the presence and thickness of the undercoat layer in the negative electrode current collector.
  • Table 6 summarizes the negative electrode production conditions (slurry coating speed, slurry drying temperature, press temperature) in Comparative Examples 1 to 11.
  • Table 6 shows the peel strength ⁇ between the negative electrode current collector and the negative electrode mixture layer, the cutting strength ⁇ in the negative electrode mixture layer, and the ratio ( ⁇ / The value of ⁇ ) is further shown.
  • Example 1 As the negative electrode active material, the same lithium titanate (Li 4 Ti 5 O 12 ) particles as those used in Example 1 were prepared. 90% by weight of this lithium titanate, 5% by weight of acetylene black as a conductive agent, 5% by weight of polyvinylidene fluoride (PVdF) (Kureha Co., Ltd. KF # 1700) as a binder, and N-methyl A slurry was prepared by dispersing in a pyrrolidone (NMP) solvent.
  • NMP pyrrolidone
  • the slurry was applied to both sides of a negative electrode current collector, which was an aluminum foil having a thickness of 15 ⁇ m and an undercoat layer (carbon resin layer) having a thickness of 1 ⁇ m formed on both surfaces. At this time, a portion of the negative electrode current collector where the slurry was not applied was left on the surface.
  • a negative electrode current collector which was an aluminum foil having a thickness of 15 ⁇ m and an undercoat layer (carbon resin layer) having a thickness of 1 ⁇ m formed on both surfaces.
  • the applied slurry was dried and pressed to form a negative electrode mixture layer having a thickness of 20 ⁇ m on one side and an electrode density of 2.0 g / cm 3 on the negative electrode current collector.
  • the coating speed, drying temperature, and press temperature at this time were performed under the conditions shown in Table 6.
  • a portion of the negative electrode current collector where the negative electrode mixture layer was not formed on the surface was punched into a band shape to form a negative electrode current collector tab. In this way, a negative electrode was produced.
  • a nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 1 except that this negative electrode was used. This was designated as the secondary battery of Comparative Example 1.
  • Example 2 As the negative electrode active material, the same lithium titanate (Li 4 Ti 5 O 12 ) particles as those used in Example 1 were prepared. 90% by weight of this lithium titanate, 7% by weight of acetylene black as a conductive agent, 3% by weight of polyvinylidene fluoride (PVdF) (Kureha KF # 1700) as a binder, and N-methyl A slurry was prepared by dispersing in a pyrrolidone (NMP) solvent.
  • PVdF polyvinylidene fluoride
  • the slurry was applied to both sides of a 15 ⁇ m-thick negative electrode current collector (without an undercoat layer), which was an aluminum foil. At this time, a portion of the negative electrode current collector where the slurry was not applied was left on the surface.
  • the applied slurry was dried and pressed to form a negative electrode mixture layer having a thickness of 20 ⁇ m on one side and an electrode density of 2.0 g / cm 3 on the negative electrode current collector.
  • the coating speed, drying temperature, and press temperature at this time were performed under the conditions shown in Table 6.
  • a portion of the negative electrode current collector where the negative electrode mixture layer was not formed on the surface was punched into a band shape to form a negative electrode current collector tab. In this way, a negative electrode was produced.
  • a nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 1 except that this negative electrode was used. This was designated as the secondary battery of Comparative Example 2.
  • Example 3 As the negative electrode active material, the same lithium titanate (Li 4 Ti 5 O 12 ) particles as those used in Example 1 were prepared. 90% by weight of this lithium titanate, 7% by weight of acetylene black as a conductive agent, and 3% by weight of polyacrylic acid (average molecular weight 450,000) as a binder were blended into an N-methylpyrrolidone (NMP) solvent. The slurry was prepared by dispersing.
  • NMP N-methylpyrrolidone
  • the slurry was applied to both sides of a 15 ⁇ m-thick negative electrode current collector (without an undercoat layer), which was an aluminum foil. At this time, a portion of the negative electrode current collector where the slurry was not applied was left on the surface.
  • the applied slurry was dried and pressed to form a negative electrode mixture layer having a thickness of 20 ⁇ m on one side and an electrode density of 2.0 g / cm 3 on the negative electrode current collector.
  • the coating speed, drying temperature, and press temperature at this time were performed under the conditions shown in Table 6.
  • a portion of the negative electrode current collector where the negative electrode mixture layer was not formed on the surface was punched into a band shape to form a negative electrode current collector tab. In this way, a negative electrode was produced.
  • a nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 1 except that this negative electrode was used. This was designated as the secondary battery of Comparative Example 3.
  • Example 4 As the negative electrode active material, the same lithium titanate (Li 4 Ti 5 O 12 ) particles as those used in Example 1 were prepared. 90% by weight of this lithium titanate, 5% by weight of acetylene black as a conductive agent, and 5% by weight of polyacrylonitrile as a binder were mixed and dispersed in an N-methylpyrrolidone (NMP) solvent to prepare a slurry. .
  • NMP N-methylpyrrolidone
  • the slurry was applied to both sides of a 15 ⁇ m-thick negative electrode current collector (without an undercoat layer), which was an aluminum foil. At this time, a portion of the negative electrode current collector where the slurry was not applied was left on the surface.
  • the applied slurry was dried and pressed to form a negative electrode mixture layer having a thickness of 20 ⁇ m on one side and an electrode density of 2.0 g / cm 3 on the negative electrode current collector.
  • the coating speed, drying temperature, and press temperature at this time were performed under the conditions shown in Table 6.
  • a portion of the negative electrode current collector where the negative electrode mixture layer was not formed on the surface was punched into a band shape to form a negative electrode current collector tab. In this way, a negative electrode was produced.
  • a nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 1 except that this negative electrode was used. This was designated as the secondary battery of Comparative Example 4.
  • Example 5 As the negative electrode active material, the same lithium titanate (Li 4 Ti 5 O 12 ) particles as those used in Example 1 were prepared. 90% by weight of this lithium titanate, 7% by weight of acetylene black as a conductive agent and 3% by weight of polyacrylonitrile as a binder were blended and dispersed in an N-methylpyrrolidone (NMP) solvent to prepare a slurry. .
  • NMP N-methylpyrrolidone
  • This slurry was applied to the surface of a 15 ⁇ m-thick negative electrode current collector (no undercoat layer), which was an aluminum foil.
  • the wettability of the negative electrode current collector with respect to the slurry was poor, and a repellency phenomenon occurred, and a uniform negative electrode could not be produced.
  • Example 6 As the negative electrode active material, the same lithium titanate (Li 4 Ti 5 O 12 ) particles as those used in Example 1 were prepared. 90% by weight of this lithium titanate, 3% by weight of acetylene black as a conductive agent and 7% by weight of polyacrylonitrile as a binder were blended and dispersed in an N-methylpyrrolidone (NMP) solvent to prepare a slurry. .
  • NMP N-methylpyrrolidone
  • This slurry was applied to both surfaces of a negative electrode current collector, which was an aluminum foil having a thickness of 15 ⁇ m and an undercoat layer (carbon resin layer) having a thickness of 0.3 ⁇ m formed on both surfaces. At this time, a portion of the negative electrode current collector where the slurry was not applied was left on the surface.
  • the applied slurry was dried and pressed to form a negative electrode mixture layer having a thickness of 20 ⁇ m on one side and an electrode density of 2.0 g / cm 3 on the negative electrode current collector.
  • the coating speed, drying temperature, and press temperature at this time were performed under the conditions shown in Table 6.
  • a portion of the negative electrode current collector where the negative electrode mixture layer was not formed on the surface was punched into a band shape to form a negative electrode current collector tab. In this way, a negative electrode was produced.
  • a nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 1 except that this negative electrode was used. This was designated as the secondary battery of Comparative Example 6.
  • Example 7 As the negative electrode active material, the same lithium titanate (Li 4 Ti 5 O 12 ) particles as those used in Example 1 were prepared. 90% by weight of this lithium titanate, 5% by weight of acetylene black as a conductive agent, and 5% by weight of polyacrylic acid (average molecular weight of 3 million) as a binder were blended into an N-methylpyrrolidone (NMP) solvent. The slurry was prepared by dispersing.
  • NMP N-methylpyrrolidone
  • the slurry was applied to both sides of a 15 ⁇ m-thick negative electrode current collector (without an undercoat layer), which was an aluminum foil. At this time, a portion of the negative electrode current collector where the slurry was not applied was left on the surface.
  • the applied slurry was dried and pressed to form a negative electrode mixture layer having a thickness of 20 ⁇ m on one side and an electrode density of 2.0 g / cm 3 on the negative electrode current collector.
  • the coating speed, drying temperature, and press temperature at this time were performed under the conditions shown in Table 6.
  • a portion of the negative electrode current collector where the negative electrode mixture layer was not formed on the surface was punched into a band shape to form a negative electrode current collector tab. In this way, a negative electrode was produced.
  • a nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 1 except that this negative electrode was used. This was designated as the secondary battery of Comparative Example 7.
  • Example 8 As the negative electrode active material, the same monoclinic titanium composite oxide (TiO 2 ) as used in Example 10 was prepared. 90% by weight of this titanium composite oxide, 6% by weight of acetylene black as a conductive agent, and 4% by weight of polymer type polyvinylidene fluoride (PVdF) (Kureha Corporation KF # 7300) as a binder. The slurry was prepared by dispersing in N-methylpyrrolidone (NMP) solvent.
  • NMP N-methylpyrrolidone
  • a negative electrode current collector which is an aluminum foil having a thickness of 15 ⁇ m and an undercoat layer (carbon resin layer) having a thickness of 0.3 ⁇ m formed on both surfaces.
  • the applied slurry was dried and pressed to form a negative electrode mixture layer having a thickness of 19 ⁇ m on one side and an electrode density of 2.0 g / cm 3 on the negative electrode current collector.
  • the coating speed, drying temperature, and press temperature at this time were performed under the conditions shown in Table 6.
  • a portion of the negative electrode current collector where the negative electrode mixture layer was not formed on the surface was punched into a band shape to form a negative electrode current collector tab. In this way, a negative electrode was produced.
  • a nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 1 except that this negative electrode was used. This was designated as the secondary battery of Comparative Example 8.
  • Example 9 The same niobium-containing titanium composite oxide (TiNb 2 O 7 ) as that used in Example 11 was prepared as the negative electrode active material. 90% by weight of this niobium-containing titanium composite oxide, 6% by weight of acetylene black as a conductive agent, and 4% by weight of polymer-type polyvinylidene fluoride (PVdF) (Kureha KF # 7300) as a binder. A slurry was prepared by mixing and dispersing in an N-methylpyrrolidone (NMP) solvent.
  • NMP N-methylpyrrolidone
  • this slurry was applied to both surfaces of a negative electrode current collector, which is an aluminum foil having a thickness of 15 ⁇ m and an undercoat layer (carbon resin layer) having a thickness of 0.3 ⁇ m formed on both surfaces. Applied.
  • the applied slurry was dried and pressed to form a negative electrode mixture layer having a thickness of 15 ⁇ m on one side and an electrode density of 2.4 g / cm 3 on the negative electrode current collector.
  • the coating speed, drying temperature, and press temperature at this time were performed under the conditions shown in Table 6.
  • a portion of the negative electrode current collector where the negative electrode mixture layer was not formed on the surface was punched into a band shape to form a negative electrode current collector tab. In this way, a negative electrode was produced.
  • a nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 1 except that this negative electrode was used. This was designated as the secondary battery of Comparative Example 9.
  • Example 10 The same sodium-containing titanium composite oxide (Li 2 Na 2 Ti 6 O 14 ) as that used in Example 12 was prepared as the negative electrode active material. 90% by weight of this sodium-containing titanium composite oxide, 6% by weight of acetylene black as a conductive agent, and 4% by weight of polymer type polyvinylidene fluoride (PVdF) (KF # 7300 manufactured by Kureha Corporation) as a binder. A slurry was prepared by mixing and dispersing in an N-methylpyrrolidone (NMP) solvent.
  • NMP N-methylpyrrolidone
  • a negative electrode current collector which is an aluminum foil having a thickness of 15 ⁇ m and an undercoat layer (carbon resin layer) having a thickness of 0.3 ⁇ m formed on both surfaces.
  • the applied slurry was dried and pressed to form a negative electrode mixture layer having a thickness of 20 ⁇ m on one side and an electrode density of 2.0 g / cm 3 on the negative electrode current collector.
  • the coating speed, drying temperature, and press temperature at this time were performed under the conditions shown in Table 6.
  • a nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 1 except that this negative electrode was used. This was designated as the secondary battery of Comparative Example 10.
  • graphite powder (mesophase spherules) having an average particle size of 10 ⁇ m was prepared. This graphite powder was mixed at 95% by weight, 5% by weight of polyacrylic acid (average molecular weight 450,000) as a binder, and N-methylpyrrolidone (NMP) was added to a solid content ratio of 70% by weight. . This was kneaded with a planetary mixer (Hibis Disperse Mix 3D-05 manufactured by PRIMIX Corporation), and the slurry was adjusted by gradually reducing the solid content ratio while adding NMP.
  • NMP N-methylpyrrolidone
  • the slurry was wet pulverized and dispersed using a continuous bead mill (RMH-03, manufactured by IMEX Co., Ltd.) under the conditions of a rotational speed of 1500 rpm and a flow rate of 30 cc / min to prepare a slurry.
  • a continuous bead mill manufactured by IMEX Co., Ltd.
  • a negative electrode current collector which is a copper foil having a thickness of 15 ⁇ m and an undercoat layer (carbon resin layer) having a thickness of 0.3 ⁇ m formed on both surfaces.
  • the coating was applied at a coating speed of 1 m / min with a coater (manufactured by Yasui Seiki Co., Ltd.) and dried at a drying temperature of 140 ° C.
  • the obtained coated electrode was pressed at a press temperature of 80 ° C. by a roll press apparatus (manufactured by Ohno Roll), and a negative electrode mixture layer having a thickness of 30 ⁇ m per side and an electrode density of 1.4 g / cm 3 was formed as a negative electrode. Formed on the current collector. Next, a portion of the negative electrode current collector where the negative electrode mixture layer was not formed on the surface was punched into a band shape to form a negative electrode current collector tab. In this way, a negative electrode was produced.
  • a liquid nonaqueous electrolyte was prepared as follows. Ethylene carbonate (EC) and diethyl carbonate (DEC) were mixed at a volume ratio of 1: 1 to obtain a mixed solvent. LiPF 6 which is an electrolyte was dissolved in this mixed solvent at 1.5 mol / L to prepare a liquid non-aqueous electrolyte.
  • a nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 1 except that the negative electrode obtained as described above and a liquid nonaqueous electrolyte were used. This was designated as the secondary battery of Comparative Example 11.
  • FIG. 7 shows a cross-sectional SEM image when the SEM measurement was performed on the negative electrode produced in Example 1 as described above.
  • Example 1 as the negative electrode current collector, an aluminum foil having an undercoat layer having a thickness of 1 ⁇ m formed on the surface thereof was used.
  • the undercoat layer 3c is disposed between the aluminum foil (negative electrode current collector 3a) and the negative electrode mixture layer 3b.
  • FIG. 8 shows a cross-sectional SEM image of the negative electrode produced in Comparative Example 4.
  • an aluminum foil having no undercoat layer was used as the negative electrode current collector.
  • the negative electrode mixture layer 3b is directly formed on the surface of the aluminum foil (negative electrode current collector 3a).
  • the secondary batteries of Examples 1 to 9, and Example 13, and Comparative Examples 1 to 4 and Comparative Examples 6 to 7 are up to 2.7 V at a constant current of 1 A (1 C) under a temperature condition of 25 ° C.
  • constant current-constant voltage charging in which charging was performed at a constant voltage, was performed. This state was set to SOC 100%.
  • capacitance when discharged to 1.5V with the electric current value of 1A (1C) was measured.
  • the secondary batteries of Examples 10 to 11 and Comparative Examples 8 to 9 were charged at a constant voltage after being charged to 2.8 V with a constant current of 1 A (1 C) under a temperature condition of 25 ° C. -A constant voltage charge was performed. This state was set to SOC 100%. Then, the capacity
  • the secondary battery of Comparative Example 11 was charged at a constant current of 1 A (1 C) to 4.2 V under a temperature condition of 25 ° C., and then was subjected to a constant current-constant voltage charge charged at a constant voltage. This state was set to SOC 100%. Then, the capacity
  • Table 7 shows the results of the initial discharge capacity measurements obtained for the secondary batteries of Examples 1 to 13 and Comparative Examples 1 to 4 and 6 to 9.
  • each of the secondary batteries of Examples 1 to 13 and Comparative Examples 1 to 4 and 6 to 11 was charged at a charging rate of 100% under a temperature condition of 25 ° C.
  • a large current discharge test was conducted in which discharge was continuously performed at a current value of 1A (1C) and 30A (30C) from the state of SOC 100%.
  • the discharge capacity ratio (C 30 / C 1 ) obtained when discharging at each current value is shown in Table 7 as the large current discharge capacity ratio.
  • each of the secondary batteries of Examples 1 to 13 and Comparative Examples 1 to 4 and 6 to 11 was subjected to a cycle test at a temperature of 80 ° C. The resistance increase rate was obtained.
  • each secondary battery is discharged at a current value of 1C (1A) and 10C (10A) from a state where the charging rate is 50% (SOC 50%), and the cell resistance value is calculated from the cell voltage 10 seconds after the discharge. (R 1 ) was calculated.
  • the resistance value (R 500 ) after 500 cycles was measured in the same manner as the measurement of the resistance value (R 1 ) after one cycle when 500 cycles had elapsed. From the resistance value (R 1 ) after one cycle and the resistance value (R 500 ) after 500 cycles, the rate of increase in resistance (R 500 / R 1 ) was determined. The results are also shown in Table 7.
  • the peel strength ⁇ as described in detail above using an electrode peel strength measuring device (rheometer) manufactured by Rheotech Co., Ltd. (Peel strength) was measured.
  • the force (gf / 2 cm) required to peel the negative electrode mixture layer 2 cm from the negative electrode current collector was determined, and this was converted into a unit and recorded as the peel strength ⁇ (N / m).
  • the negative electrode was cut off to 20 square mm and it was set as the evaluation sample for cutting strength.
  • Examples 1 to 13 are superior to Comparative Examples 1 to 4 and 6 to 10 in terms of output performance, have a long cycle life, and can exhibit excellent high temperature durability.
  • Examples 1 to 13 have a smaller resistance increase rate under high temperature conditions and excellent high temperature durability than Comparative Examples 1 to 4 and 6 to 10.
  • a non-aqueous electrolyte secondary battery includes a positive electrode, a negative electrode, and a non-aqueous electrolyte.
  • the negative electrode includes a negative electrode current collector and a negative electrode mixture layer disposed on the negative electrode current collector.
  • the negative electrode current collector includes a metal foil.
  • the negative electrode mixture layer contains a titanium-containing metal oxide that occludes and releases lithium ions and a binder containing an acrylic resin.
  • the peel strength ⁇ (N / m) between the negative electrode current collector and the negative electrode mixture layer and the cutting strength ⁇ (N / m) measured by the surface / interface cutting method in the negative electrode mixture layer are ⁇ / ⁇ > The relationship of 1.36 ⁇ 10 ⁇ 2 is satisfied.
  • This non-aqueous electrolyte secondary battery is excellent in output performance and excellent in high temperature durability.

Abstract

This nonaqueous electrolyte secondary battery comprises a positive electrode, a negative electrode and a nonaqueous electrolyte. The negative electrode comprises a negative electrode collector and a negative electrode mixture layer that is arranged on the negative electrode collector. The negative electrode collector comprises a metal foil. The negative electrode mixture layer contains: a titanium-containing metal oxide that absorbs and desorbs lithium ions; and a binder that contains an acrylic resin. This negative electrode satisfies the following formula (I). α/β > 1.36 × 10-2 (I) (In the formula, α represents the peel strength (N/m) between the collector and the negative electrode mixture layer; and β represents the cutting strength (N/m) of the negative electrode mixture layer as determined by a surface/interface cutting method.)

Description

非水電解質二次電池および電池パックNonaqueous electrolyte secondary battery and battery pack
　本実施形態は、非水電解質二次電池および電池パックに係わる。 This embodiment relates to a non-aqueous electrolyte secondary battery and a battery pack.
　近年、Ｌｉイオンが負極と正極とを移動することにより充放電が行われる非水電解質二次電池について、高エネルギー密度電池としての研究開発が盛んに進められている。これまでに、活物質としてＬｉＣｏＯ２またはＬｉＭｎ２Ｏ４を含む正極と、リチウムを吸蔵および放出する炭素質物を含む負極とを具備したリチウムイオン二次電池が、携帯機器用に広く実用化されている。 In recent years, research and development as a high energy density battery has been actively conducted on a non-aqueous electrolyte secondary battery in which charging and discharging are performed by movement of Li ions between a negative electrode and a positive electrode. So far, lithium ion secondary batteries having a positive electrode containing LiCoO 2 or LiMn 2 O 4 as an active material and a negative electrode containing a carbonaceous material that occludes and releases lithium have been widely put into practical use for portable devices. Yes.
　このようなリチウムイオン二次電池は、近年、環境問題の観点から開発されている、電気自動車（electric vehicle；ＥＶ）、ハイブリッド車(hybrid electric vehicle；ＨＥＶ)、プラグインハイブリッド車(plug-in hybrid electric vehicle；ＰＨＥＶ)、アイドリングストップシステム(idling-stop system；ＩＳＳ)搭載車等の環境対応車用の電源として多用されている。リチウムイオン二次電池を電気自動車やハイブリッド車等の車両に搭載する場合、リチウムイオン二次電池には、高温環境下での貯蔵性能、サイクル性能、高出力の長期信頼性等が要求される。 Such lithium ion secondary batteries have recently been developed from the viewpoint of environmental problems, such as electric vehicles (EV), hybrid vehicles (HEV), plug-in hybrid vehicles (plug-in hybrid vehicles). It is widely used as a power source for environmentally friendly vehicles such as electric vehicles (PHEV) and idling-stop systems (ISS). When a lithium ion secondary battery is mounted on a vehicle such as an electric vehicle or a hybrid vehicle, the lithium ion secondary battery is required to have storage performance in a high temperature environment, cycle performance, high output long-term reliability, and the like.
　また、鉛蓄電池の代替として自動車のエンジンルームに搭載して使用する場合には、リチウムイオン二次電池に高温耐久性（例えば、８０℃以上）が求められている。さらに、寒冷地での高い性能が要求される場合、低温環境下（例えば－３０℃）での高出力性能や長寿命性能が必要となる。 In addition, when used in an engine room of an automobile as an alternative to a lead storage battery, the lithium ion secondary battery is required to have high temperature durability (for example, 80 ° C. or higher). Furthermore, when high performance is required in a cold region, high output performance and long life performance in a low temperature environment (for example, −30 ° C.) are required.
　そのため、正極、負極、セパレータ、電解液といった電池の構成材料には、高温および低温での化学的、電気化学的な安定性、強度、耐腐食性に優れた材料が求められる。 For this reason, materials that are excellent in chemical and electrochemical stability, strength, and corrosion resistance at high and low temperatures are required for battery constituent materials such as positive electrodes, negative electrodes, separators, and electrolytes.
　ところで、リチウムイオン二次電池に用いられる負極は、通常、負極活物質層が集電体上に形成された構造を有している。この負極活物質層には、負極活物質の他、負極活物質同士および負極活物質と集電体とを結着させるための結着剤が用いられている。 Incidentally, the negative electrode used in the lithium ion secondary battery usually has a structure in which a negative electrode active material layer is formed on a current collector. In addition to the negative electrode active material, a negative electrode active material and a binder for binding the negative electrode active material and the current collector are used for the negative electrode active material layer.
　結着剤としては、一般にフッ素系樹脂（例えば、polyvinylidene fluoride；ＰＶｄＦ）やその変性体が用いられている。しかしながら、フッ素系樹脂やその変性体は、高温においては電解液に対して膨潤しやすい。そのため、結着剤としてフッ素系樹脂やその変性体を含んだ負極を有する電池では、高温サイクル性能が低下するおそれがあった。具体的には、このようなフッ素系樹脂などを負極の結着剤に用いている電池においては、高温での充放電サイクルに伴い負極の電子伝導のネットワークが切断され、その結果、負極の内部抵抗が上昇する。 As the binder, a fluorine-based resin (for example, polyvinylidene fluoride; PVdF) or a modified product thereof is generally used. However, fluorine-based resins and their modified products easily swell with respect to the electrolyte solution at high temperatures. For this reason, in a battery having a negative electrode containing a fluorine-based resin or a modified product thereof as a binder, the high-temperature cycle performance may be deteriorated. Specifically, in a battery using such a fluorine-based resin as a binder for a negative electrode, the network of electron conduction of the negative electrode is cut off with a charge / discharge cycle at a high temperature. Resistance rises.
　そこで、ＰＶｄＦなどのフッ素系樹脂の代わりにアクリル系樹脂などの合成ゴム質重合体が負極の結着剤として提案されている。 Therefore, synthetic rubbery polymers such as acrylic resins instead of fluorine resins such as PVdF have been proposed as binders for negative electrodes.
ＷＯ２０１１／００２０５７　Ａ１WO2011 / 002057 A1 特開２０１２－１７４５７７JP2012-174577 特開２００８－０９８５９０JP2008-098590 特開２０１４－０１７１９９JP 2014-0117199 A ＷＯ２０１４／０６８９０５　Ａ１WO2014 / 068905 A1 ＷＯ２０１４／１５７０１０　Ａ１WO2014 / 157010 A1 特開２０１３－０２３６５４JP2013-023654A
　実施形態の目的は、高温耐久性に優れた非水電解質二次電池、該非水電解質二次電池を具備する電池パック、並びに該電池パックを具備する自動車を提供することにある。 An object of the embodiment is to provide a non-aqueous electrolyte secondary battery excellent in high temperature durability, a battery pack including the non-aqueous electrolyte secondary battery, and an automobile including the battery pack.
　実施形態によると、非水電解質二次電池が提供される。この非水電解質二次電池は、正極と、負極と、非水電解質とを含む。負極は、負極集電体と、この負極集電体上に配置されている負極合剤層とを含む。負極集電体は、金属箔を含んでいる。負極合剤層は、リチウムイオンを吸蔵および放出するチタン含有金属酸化物とアクリル系樹脂を含む結着剤とを含んでいる。この負極は、下記式（Ｉ）を満たす。
　　　α／β＞１．３６×１０－２　（Ｉ）
ここで、αは前記集電体と前記負極合剤層との剥離強度（Ｎ／ｍ）であり、βは前記負極合剤層における表面・界面切削法により測定される切削強度（Ｎ／ｍ）である。 According to the embodiment, a non-aqueous electrolyte secondary battery is provided. This non-aqueous electrolyte secondary battery includes a positive electrode, a negative electrode, and a non-aqueous electrolyte. The negative electrode includes a negative electrode current collector and a negative electrode mixture layer disposed on the negative electrode current collector. The negative electrode current collector includes a metal foil. The negative electrode mixture layer contains a titanium-containing metal oxide that occludes and releases lithium ions and a binder containing an acrylic resin. This negative electrode satisfies the following formula (I).
α / β> 1.36 × 10 −2 (I)
Here, α is the peel strength (N / m) between the current collector and the negative electrode mixture layer, and β is the cutting strength (N / m) measured by the surface / interface cutting method in the negative electrode mixture layer. ).
実施形態の一例である扁平型非水電解質二次電池の断面図である。It is sectional drawing of the flat type nonaqueous electrolyte secondary battery which is an example of embodiment. 図１のＡ部の拡大断面図である。It is an expanded sectional view of the A section of FIG. 実施形態の他の例である扁平型非水電解質二次電池の模式図である。It is a schematic diagram of the flat type nonaqueous electrolyte secondary battery which is another example of embodiment. 図３のＢ部の拡大断面図である。It is an expanded sectional view of the B section of FIG. 実施形態の電池パックの分解斜視図である。It is a disassembled perspective view of the battery pack of embodiment. 図５の電池パックの電気回路を示すブロック図である。It is a block diagram which shows the electric circuit of the battery pack of FIG. 一つの実施例における負極の断面の走査型電子顕微鏡(scanning electron microscope; ＳＥＭ)像である。2 is a scanning electron microscope (scanSEM) image of a cross-section of a negative electrode in one example. 一つの比較例における負極の断面のＳＥＭ像である。It is a SEM image of the cross section of the negative electrode in one comparative example.
　以下、図面を参照しながら、実施の形態を説明する。以下の図面の記載において同一又は類似の部分には同一又は類似の符号を付し、重複する記載は省略する。但し、図面は模式的なものであり、厚みと平面寸法との関係、各層の厚みの比率等は現実のものとは異なる場合があることに留意すべきである。したがって、具体的な厚みや寸法は以下の説明を参酌して判断すべきものである。図面相互間においても互いの寸法の関係や比率が異なる部分が含まれていることは勿論である。 Hereinafter, embodiments will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals, and overlapping descriptions are omitted. However, it should be noted that the drawings are schematic, and the relationship between the thickness and the planar dimensions, the ratio of the thickness of each layer, and the like may differ from the actual ones. Therefore, specific thicknesses and dimensions should be determined in consideration of the following description. It goes without saying that the drawings include parts having different dimensional relationships and ratios.
　また、以下に示す実施の形態は、発明の技術的思想を具体化するための装置や方法を例示するものであって、発明の技術的思想は、構成部品の材質、形状、構造、配置等を下記のものに特定するものでない。発明の技術的思想は、請求の範囲において、種々の変更を加えることができる。 The embodiments described below exemplify apparatuses and methods for embodying the technical idea of the invention, and the technical idea of the invention is the material, shape, structure, arrangement, etc. of the component parts. Is not specified as follows. The technical idea of the invention can be variously modified within the scope of the claims.
　［第１の実施形態］
　第１の実施形態によると、非水電解質二次電池が提供される。この非水電解質二次電池は、正極と、負極と、非水電解質とを含む。負極は、金属箔を含んだ負極集電体と、この負極集電体の上に配置され、負極活物質と結着剤とを含んだ負極合剤層とを含む。負極合剤層に含まれている負極活物質は、リチウムイオンを吸蔵および放出することのできるチタン含有金属酸化物を含む。また、結着剤は、アクリル系樹脂を含む。負極集電体と負極合剤層との剥離強度α（単位：Ｎ／ｍ）と、負極合剤層において表面・界面切削法により測定される切削強度β（単位：Ｎ／ｍ）とは、α／β＞１．３６×１０－２の関係を満たす。 [First Embodiment]
According to the first embodiment, a non-aqueous electrolyte secondary battery is provided. This non-aqueous electrolyte secondary battery includes a positive electrode, a negative electrode, and a non-aqueous electrolyte. The negative electrode includes a negative electrode current collector including a metal foil, and a negative electrode mixture layer disposed on the negative electrode current collector and including a negative electrode active material and a binder. The negative electrode active material contained in the negative electrode mixture layer contains a titanium-containing metal oxide that can occlude and release lithium ions. Further, the binder contains an acrylic resin. The peel strength α (unit: N / m) between the negative electrode current collector and the negative electrode mixture layer and the cutting strength β (unit: N / m) measured by the surface / interface cutting method in the negative electrode mixture layer are: The relationship of α / β> 1.36 × 10 −2 is satisfied.
　第１の実施形態に係る非水電解質二次電池を図１、図２を参照してより具体的に説明する。図１は、第１の実施形態に係る扁平型非水電解質二次電池の断面図、図２は図１のＡ部の拡大断面図を示す。 The nonaqueous electrolyte secondary battery according to the first embodiment will be described more specifically with reference to FIGS. FIG. 1 is a cross-sectional view of a flat type nonaqueous electrolyte secondary battery according to the first embodiment, and FIG. 2 is an enlarged cross-sectional view of part A of FIG.
　扁平状の捲回電極群１は、２枚の樹脂フィルムの間に金属層を介在したラミネートフィルムからなる袋状外装部材２内に収納されている。扁平状の捲回電極群１は、外側から負極３、セパレータ４、正極５、セパレータ４の順で積層した積層物を渦巻状に捲回し、この積層物をプレス成型することにより形成される。最外層の負極３は、図１に示すように負極集電体３ａの内面側の片面に負極活物質を含む負極合剤層３ｂを形成した構成を有し、その他の負極３は、負極集電体３ａの両面に負極合剤層３ｂを形成して構成されている。正極５は、正極集電体５ａの両面に正極合剤層５ｂを形成して構成されている。 The flat wound electrode group 1 is housed in a bag-shaped exterior member 2 made of a laminate film having a metal layer interposed between two resin films. The flat wound electrode group 1 is formed by winding a laminate in which the negative electrode 3, the separator 4, the positive electrode 5, and the separator 4 are laminated in this order from the outside, and then press-molding the laminate. As shown in FIG. 1, the outermost negative electrode 3 has a configuration in which a negative electrode mixture layer 3b containing a negative electrode active material is formed on one surface on the inner surface side of a negative electrode current collector 3a. The negative electrode mixture layer 3b is formed on both surfaces of the electric body 3a. The positive electrode 5 is configured by forming a positive electrode mixture layer 5b on both surfaces of a positive electrode current collector 5a.
　捲回電極群１の外周端近傍において、負極端子６は最外層の負極３の負極集電体３ａに接続され、正極端子７は内側の正極５の正極集電体５ａに接続されている。これらの負極端子６および正極端子７は、袋状外装部材２の開口部から外部に延出されている。例えば液状非水電解質は、袋状外装部材２の開口部から注入されている。袋状外装部材２の開口部をヒートシールすることにより捲回電極群１および液状非水電解質を完全密封している。ヒートシールする際、負極端子６および正極端子７は、この開口部にて袋状外装部材２により挟まれる。 In the vicinity of the outer peripheral end of the wound electrode group 1, the negative electrode terminal 6 is connected to the negative electrode current collector 3 a of the outermost negative electrode 3, and the positive electrode terminal 7 is connected to the positive electrode current collector 5 a of the inner positive electrode 5. The negative electrode terminal 6 and the positive electrode terminal 7 are extended to the outside from the opening of the bag-shaped exterior member 2. For example, the liquid nonaqueous electrolyte is injected from the opening of the bag-shaped exterior member 2. The wound electrode group 1 and the liquid nonaqueous electrolyte are completely sealed by heat-sealing the opening of the bag-shaped exterior member 2. When heat-sealing, the negative electrode terminal 6 and the positive electrode terminal 7 are sandwiched by the bag-shaped exterior member 2 at this opening.
　第１の実施形態に係る非水電解質二次電池は、前述した図１および図２に示す構成のものに限らず、例えば図３および図４に示す構成にすることができる。図３は、第１の実施形態に係る別の扁平型非水電解質二次電池を模式的に示す部分切欠斜視図で、図４は図３のＢ部の拡大断面図である。 The non-aqueous electrolyte secondary battery according to the first embodiment is not limited to the configuration shown in FIGS. 1 and 2 described above, and can be configured as shown in FIGS. 3 and 4, for example. FIG. 3 is a partially cutaway perspective view schematically showing another flat type nonaqueous electrolyte secondary battery according to the first embodiment, and FIG. 4 is an enlarged cross-sectional view of a portion B in FIG. 3.
　積層型電極群１１は、２枚の樹脂フィルムの間に金属層を介在したラミネートフィルムからなる外装部材１２内に収納されている。積層型電極群１１は、図４に示すように正極１３と負極１４とをその間にセパレータ１５を介在させながら交互に積層した構造を有する。正極１３は複数枚存在し、それぞれが正極集電体１３ａと、正極集電体１３ａの両面に担持された正極合剤層１３ｂとを備える。負極１４は複数枚存在し、それぞれが負極集電体１４ａと、負極集電体１４ａの両面に担持された負極合剤層１４ｂとを備える。各負極１４の負極集電体１４ａは、一端が正極１３から突出している。負極集電体１４ａの突出している一端は、帯状の負極端子１６に電気的に接続されている。帯状の負極端子１６の先端は、外装部材１２から外部に引き出されている。また、図示しないが、正極１３の正極集電体１３ａは、一端が負極１４から突出している。負極１４から突出している正極１３ａの一端は、負極集電体１４ａの突出している一端と反対側に位置する。正極集電体１３ａの突出している一端は、帯状の正極端子１７に電気的に接続されている。帯状の正極端子１７の先端は、負極端子１６とは反対側に位置し、外装部材１２の辺から外部に引き出されている。 The laminated electrode group 11 is housed in an exterior member 12 made of a laminate film in which a metal layer is interposed between two resin films. As shown in FIG. 4, the stacked electrode group 11 has a structure in which positive electrodes 13 and negative electrodes 14 are alternately stacked with separators 15 interposed therebetween. There are a plurality of positive electrodes 13, each of which includes a positive electrode current collector 13 a and a positive electrode mixture layer 13 b supported on both surfaces of the positive electrode current collector 13 a. There are a plurality of negative electrodes 14, each including a negative electrode current collector 14 a and a negative electrode mixture layer 14 b carried on both surfaces of the negative electrode current collector 14 a. One end of the negative electrode current collector 14 a of each negative electrode 14 protrudes from the positive electrode 13. The projecting end of the negative electrode current collector 14 a is electrically connected to the strip-shaped negative electrode terminal 16. The tip of the strip-shaped negative electrode terminal 16 is drawn out from the exterior member 12 to the outside. Although not shown, one end of the positive electrode current collector 13 a of the positive electrode 13 protrudes from the negative electrode 14. One end of the positive electrode 13a protruding from the negative electrode 14 is located on the opposite side to the one end of the negative electrode current collector 14a protruding. One end of the positive electrode current collector 13 a protruding is electrically connected to the belt-like positive electrode terminal 17. The tip of the strip-like positive electrode terminal 17 is located on the opposite side of the negative electrode terminal 16 and is drawn out from the side of the exterior member 12 to the outside.
　以下、実施形態の非水電解質二次電池に用いられる負極、正極、非水電解質、セパレータ、外装部材、正極端子、負極端子について詳細に説明する。 Hereinafter, a negative electrode, a positive electrode, a nonaqueous electrolyte, a separator, an exterior member, a positive electrode terminal, and a negative electrode terminal used in the nonaqueous electrolyte secondary battery of the embodiment will be described in detail.
　（負極）
　リチウムイオン二次電池に用いられる負極は、通常、負極活物質層（負極合剤層）が集電体上に形成された構造を有している。負極合剤層には、負極活物質の他、負極活物質同士および負極活物質と集電体とを結着させるための結着剤が用いられている。 (Negative electrode)
A negative electrode used for a lithium ion secondary battery usually has a structure in which a negative electrode active material layer (negative electrode mixture layer) is formed on a current collector. In addition to the negative electrode active material, a negative electrode active material and a binder for binding the negative electrode active material and the current collector are used in the negative electrode mixture layer.
　結着剤であるフッ素系樹脂（例えば、ＰＶｄＦ）やその変性体は、高温においては電解液に対して膨潤しやすい。そのため、これらを結着剤として用いた負極を含む電池では、高温での充放電サイクルに伴い負極の電子伝導のネットワークが切断される。その結果、負極の内部抵抗が上昇し、電池の高温サイクル性能の低下を招く。 The fluorine-based resin (for example, PVdF) that is a binder or a modified product thereof easily swells with respect to the electrolyte solution at high temperatures. Therefore, in a battery including a negative electrode using these as a binder, the network of electron conduction of the negative electrode is cut off with a charge / discharge cycle at a high temperature. As a result, the internal resistance of the negative electrode increases, leading to a decrease in the high-temperature cycle performance of the battery.
　一方、アクリル系樹脂は、フッ素系樹脂（ＰＶｄＦなど）やその変性体に比べ、電解液に対し高温で膨潤しにくい結着剤である。しかし、アクリル系樹脂を結着剤として用いた場合には、負極を作製する際に不具合が生じる場合がある。実際、本発明者らはアクリル系樹脂を結着剤として使用して負極の作製を試みたところ、次のような不具合が生じた。具体的には、結着剤としてのアクリル系樹脂、活物質、導電材としてのカーボンを分散剤（Ｎ－メチル－２－ピロリドン）に分散させてスラリーを作製した。このスラリーを集電体としてのアルミニウム箔上に塗布した。このとき、スラリーがアルミニウム箔から弾いてしまい、スラリーを所望の膜厚に塗布することが出来なかった。或いは、スラリーを塗布することは出来たとしても、集電体と負極合剤層との密着性が低下したりすることが確認された。 On the other hand, acrylic resins are binders that are less likely to swell at high temperatures with respect to electrolyte solutions than fluororesins (such as PVdF) and their modified products. However, when an acrylic resin is used as a binder, a problem may occur when a negative electrode is produced. In fact, when the present inventors tried to produce a negative electrode using an acrylic resin as a binder, the following problems occurred. Specifically, an acrylic resin as a binder, an active material, and carbon as a conductive material were dispersed in a dispersant (N-methyl-2-pyrrolidone) to prepare a slurry. This slurry was applied on an aluminum foil as a current collector. At this time, the slurry bounced from the aluminum foil, and the slurry could not be applied to a desired film thickness. Or even if the slurry could be applied, it was confirmed that the adhesion between the current collector and the negative electrode mixture layer was lowered.
　この現象は、特に負極活物質として、チタン含有金属酸化物を用いた場合に特に顕著であった。このため、非水電解質二次電池において、負極活物質としてチタン含有金属酸化物を用いている場合は、電池の高温耐久性を改善する目的で、何らの処置も講じずに単純に結着剤をアクリル系樹脂に変えただけでは、出力性能に優れ、かつ高温耐久性（サイクル性能）に優れた非水電解質二次電池を得ることは難しい。 This phenomenon was particularly remarkable when a titanium-containing metal oxide was used as the negative electrode active material. For this reason, in a nonaqueous electrolyte secondary battery, when a titanium-containing metal oxide is used as a negative electrode active material, a binder is simply used without taking any measures for the purpose of improving the high temperature durability of the battery. It is difficult to obtain a non-aqueous electrolyte secondary battery that is excellent in output performance and excellent in high-temperature durability (cycle performance) simply by changing to an acrylic resin.
　第１の実施形態に係る非水電解質二次電池では、負極は、リチウムイオンを吸蔵および放出するチタン含有金属酸化物と結着剤とを含有する負極合剤層とで構成され、結着剤はアクリル系樹脂を含む。負極集電体は、金属箔を含んでいる。負極集電体と負極合剤層との剥離強度をα（Ｎ／ｍ）とし、負極合剤層における表面・界面切削法により測定される切削強度をβ（Ｎ／ｍ）とした場合、前記αおよびβは、α／β＞１．３６×１０－２の関係を満たす。製造の条件を適切に制御することによって、このような構成を有するように作製された負極を用いれば、出力性能に優れ、かつ高温耐久性（サイクル性能）に優れた非水電解質二次電池を得ることが可能となる。 In the nonaqueous electrolyte secondary battery according to the first embodiment, the negative electrode is composed of a titanium-containing metal oxide that absorbs and releases lithium ions and a negative electrode mixture layer that contains a binder, and the binder. Includes an acrylic resin. The negative electrode current collector includes a metal foil. When the peel strength between the negative electrode current collector and the negative electrode mixture layer is α (N / m) and the cutting strength measured by the surface / interface cutting method in the negative electrode mixture layer is β (N / m), α and β satisfy the relationship of α / β> 1.36 × 10 −2 . By appropriately controlling the manufacturing conditions, a non-aqueous electrolyte secondary battery having excellent output performance and high-temperature durability (cycle performance) can be obtained by using a negative electrode made to have such a configuration. Can be obtained.
　実施形態に係る非水電解質二次電池の含む負極は、負極集電体及び負極合剤層を含む。負極合剤層は、負極活物質、導電剤及び結着剤を含む。負極合剤層は、負極集電体の片面若しくは両面に形成される。 The negative electrode included in the nonaqueous electrolyte secondary battery according to the embodiment includes a negative electrode current collector and a negative electrode mixture layer. The negative electrode mixture layer includes a negative electrode active material, a conductive agent, and a binder. The negative electrode mixture layer is formed on one side or both sides of the negative electrode current collector.
　後述するように、このような負極の作製において、負極合剤層の材料を含んだスラリーを負極集電体の上に塗布することで負極合剤層が形成される。このとき、結着剤としてアクリル系樹脂を用い、集電体としてアルミニウム箔を用いた場合に、結着剤が活物質同士を優先的に結着させてしまう結果、集電体と合剤層との密着性が低下する場合がある。上述した剥離強度αと切削強度βとが、α／β＞１．３６×１０－２の関係にある負極では、負極合剤層と負極集電体との結着に優先して負極活物質同士が結着されることがない。そのため、このような負極は、負極合剤層と負極集電体との密着性に優れる。 As will be described later, in the production of such a negative electrode, the negative electrode mixture layer is formed by applying a slurry containing the material of the negative electrode mixture layer on the negative electrode current collector. At this time, when an acrylic resin is used as the binder and an aluminum foil is used as the current collector, the binder preferentially binds the active materials to each other. As a result, the current collector and the mixture layer Adhesiveness may be reduced. In the negative electrode in which the peel strength α and the cutting strength β are in the relationship of α / β> 1.36 × 10 −2 , the negative electrode active material has priority over the binding between the negative electrode mixture layer and the negative electrode current collector. They are not bound together. Therefore, such a negative electrode is excellent in adhesion between the negative electrode mixture layer and the negative electrode current collector.
　負極集電体と負極合剤層との剥離強度αと負極合剤層における切削強度βとは、α／β＜４．９×１０－２の関係をさらに満たすことが好ましい。即ち、負極は、下記式（Ｉ）と式（ＩＩ）との両方を満たしていることが好ましい。
　　　α／β＞１．３６×１０－２　（Ｉ）
　　　α／β＜４．９×１０－２　　（ＩＩ）
ここで、αは前記負極集電体と前記負極合剤層との剥離強度（Ｎ／ｍ）であり、βは前記負極合剤層における表面・界面切削法により測定される切削強度（Ｎ／ｍ）である。 It is preferable that the peel strength α between the negative electrode current collector and the negative electrode mixture layer and the cutting strength β in the negative electrode mixture layer further satisfy the relationship of α / β <4.9 × 10 −2 . That is, the negative electrode preferably satisfies both the following formulas (I) and (II).
α / β> 1.36 × 10 −2 (I)
α / β <4.9 × 10 −2 (II)
Here, α is the peel strength (N / m) between the negative electrode current collector and the negative electrode mixture layer, and β is the cutting strength (N / M) measured by the surface / interface cutting method in the negative electrode mixture layer. m).
　負極において、α／βが４．９×１０－２以上である場合は、優れた高温耐久性が得られない場合がある。 In the negative electrode, when α / β is 4.9 × 10 −2 or more, excellent high temperature durability may not be obtained.
　また、負極集電体と負極合剤層との剥離強度αは、２．５Ｎ／ｍ以上２７Ｎ／ｍ以下であることが好ましい。剥離強度αが２．５Ｎ／ｍ未満であると、集電体との密着性が不十分であり、負極作製に支障をきたすおそれがある。また、充放電サイクルに伴い負極合剤層が負極集電体から剥離してしまうことにより電池の抵抗が増大し、サイクル性能の低下を引き起こす恐れがある。また、剥離強度αが２７Ｎ／ｍを超えると、負極自体が硬く、もろくなりやすくなる。この場合も、電池作製において支障をきたしやすい。集電体と負極合剤層との剥離強度αのさらに好ましい範囲は、３．５Ｎ／ｍ以上１０Ｎ／ｍ以下である。 The peel strength α between the negative electrode current collector and the negative electrode mixture layer is preferably 2.5 N / m or more and 27 N / m or less. When the peel strength α is less than 2.5 N / m, the adhesiveness with the current collector is insufficient, and there is a possibility of hindering the production of the negative electrode. Further, the negative electrode mixture layer is peeled off from the negative electrode current collector along with the charge / discharge cycle, whereby the resistance of the battery is increased and the cycle performance may be deteriorated. On the other hand, when the peel strength α exceeds 27 N / m, the negative electrode itself is hard and fragile. Also in this case, it is easy to cause trouble in battery production. A more preferable range of the peel strength α between the current collector and the negative electrode mixture layer is 3.5 N / m or more and 10 N / m or less.
　表面・界面切削法により測定される、負極合剤層における切削強度βは、１８０Ｎ／ｍ以上９００Ｎ／ｍ以下であることが好ましい。負極合剤層における切削強度βは、負極合剤層のせん断力に対応し得る。切削強度βが１８０Ｎ／未満の場合は、負極合剤層の強度が十分ではない可能性がある。切削強度βが９００Ｎ／ｍを超える場合は、電池の充放電に伴う膨張および収縮に、負極合剤層が耐えることができない場合がある。切削強度βは、６００Ｎ／ｍ以下であることがより好ましい。 The cutting strength β in the negative electrode mixture layer measured by the surface / interface cutting method is preferably 180 N / m or more and 900 N / m or less. The cutting strength β in the negative electrode mixture layer can correspond to the shearing force of the negative electrode mixture layer. When the cutting strength β is less than 180 N /, the strength of the negative electrode mixture layer may not be sufficient. When the cutting strength β exceeds 900 N / m, the negative electrode mixture layer may not be able to withstand the expansion and contraction associated with the charging / discharging of the battery. The cutting strength β is more preferably 600 N / m or less.
　第１の実施形態に係る非水電解質二次電池では、負極合剤層が、負極活物質としてリチウムイオンを吸蔵および放出するチタン含有金属酸化物を含む。 In the nonaqueous electrolyte secondary battery according to the first embodiment, the negative electrode mixture layer includes a titanium-containing metal oxide that absorbs and releases lithium ions as a negative electrode active material.
　チタン含有金属酸化物としては、スピネル型チタン酸リチウム、単斜晶型チタン複合酸化物、一般式Ｔｉ１－ｘＭｘ＋ｙＮｂ２－ｙＯ７-δ（０≦ｘ≦１、０≦ｙ＜１、ＭはＭｇ、Ｆｅ，Ｎｉ、Ｃｏ、Ｗ、ＴａおよびＭｏより選択される少なくとも一つを含む）で表されるニオブ－チタン複合酸化物、一般式Ｌｉ２＋ｖＮａ２－ｗＭ1ｘＴｉ６－ｙ－ｚＮｂｙＭ2ｚＯ１４＋δ（０≦ｖ≦４、０＜ｗ＜２、０≦ｘ＜２、０＜ｙ≦６、０≦ｚ＜３、－０．５≦δ≦０．５；Ｍ1は、Ｃｓ、Ｋ、Ｓｒ、Ｂａ及びＣａからなる群より選択される少なくとも１種の金属元素であり、Ｍ2は、Ｚｒ、Ｓｎ、Ｖ、Ｔａ、Ｍｏ、Ｗ、Ｆｅ、Ｃｏ、Ｍｎ及びＡｌからなる群より選択される少なくとも１種である）で表される斜方晶型Ｎａ含有ニオブチタン複合酸化物から選ばれる少なくも一つ以上を用いることができる。 The titanium-containing metal oxide, the spinel-type lithium titanate, monoclinic titanium composite oxide represented by the general formula Ti 1-x M x + y Nb 2-y O 7-δ (0 ≦ x ≦ 1,0 ≦ y < 1, M includes at least one selected from Mg, Fe, Ni, Co, W, Ta, and Mo), a niobium-titanium composite oxide represented by the general formula Li 2 + v Na 2 -w M 1 x Ti 6 −yz Nb y M2 z O 14 + δ (0 ≦ v ≦ 4, 0 <w <2, 0 ≦ x <2, 0 <y ≦ 6, 0 ≦ z <3, −0.5 ≦ δ ≦ 0. 5; M1 is at least one metal element selected from the group consisting of Cs, K, Sr, Ba and Ca, and M2 is Zr, Sn, V, Ta, Mo, W, Fe, Co, Mn And at least one selected from the group consisting of Al) and orthorhombic Na-containing niobium tita Less selected from composite oxides can be used more than one.
　第１の実施形態に係る非水電解質二次電池では、負極合剤層が、導電剤を含んでいても良い。導電剤としては、グラファイト（黒鉛）、アセチレンブラック、カーボンブラック、カーボンナノファイバー、及びカーボンナノチューブのような炭素質物が挙げられる。これらの炭素質物を単独で用いてもよいし、或いは複数の炭素質物を用いてもよい。 In the nonaqueous electrolyte secondary battery according to the first embodiment, the negative electrode mixture layer may include a conductive agent. Examples of the conductive agent include carbonaceous materials such as graphite (graphite), acetylene black, carbon black, carbon nanofibers, and carbon nanotubes. These carbonaceous materials may be used alone or a plurality of carbonaceous materials may be used.
　更に第１の実施形態に係る非水電解質二次電池では、結着剤はアクリル系樹脂（アクリル系ポリマー）を含む。アクリル系樹脂は、重合体または共重合体であってもよい。或いは、アクリル系樹脂は重合体および共重合体の両方を含んでいても良い。 Furthermore, in the nonaqueous electrolyte secondary battery according to the first embodiment, the binder includes an acrylic resin (acrylic polymer). The acrylic resin may be a polymer or a copolymer. Alternatively, the acrylic resin may contain both a polymer and a copolymer.
　アクリル系樹脂は高温において電解液に対して膨潤しにくく、高温で充放電サイクルを繰り返しても負極の電子伝導のネットワークが維持される。そのため、アクリル系樹脂を用いた負極を含んだ電池では、高温でのセル抵抗の上昇が抑制され、電池の高温サイクル性能が向上する。 The acrylic resin does not easily swell with respect to the electrolyte solution at a high temperature, and the electron conduction network of the negative electrode is maintained even when the charge / discharge cycle is repeated at a high temperature. Therefore, in a battery including a negative electrode using an acrylic resin, an increase in cell resistance at a high temperature is suppressed, and the high temperature cycle performance of the battery is improved.
　アクリル系樹脂（アクリル系ポリマー）を構成するモノマーの例には、アクリル基を有するモノマーおよびメタクリル基を有するモノマーが含まれる。アクリル基を有するモノマーは、典型的には、アクリル酸またはアクリル酸エステルである。メタクリル基を有するモノマーは、典型的には、メタクリル酸またはメタクリル酸エステルである。 Examples of the monomer constituting the acrylic resin (acrylic polymer) include a monomer having an acrylic group and a monomer having a methacryl group. The monomer having an acrylic group is typically acrylic acid or an acrylate ester. The monomer having a methacryl group is typically methacrylic acid or a methacrylic ester.
　アクリル系樹脂（アクリル系ポリマー）を構成するモノマーの例には、アクリル酸エチル、アクリル酸メチル、アクリル酸ブチル、アクリル酸２-エチルヘキシル、アクリル酸イソノニル、アクリル酸ヒドロキシエチル、メタクリル酸メチル、メタクリル酸グリシジル、アクリロニトリル、スチレン、およびアクリルアミドが含まれる。 Examples of monomers constituting the acrylic resin (acrylic polymer) include ethyl acrylate, methyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, isononyl acrylate, hydroxyethyl acrylate, methyl methacrylate, methacrylic acid Glycidyl, acrylonitrile, styrene, and acrylamide are included.
　アクリル系樹脂（アクリル系ポリマー）としては、ニトリル基を含むアクリル系樹脂を主体とするものが好ましい。具体的には、ポリアクリロニトリルを主体とするものが挙げられる。このような結着剤は、負極活物質であるチタン含有金属酸化物との相互作用が特に強い。これは、ポリアクリロニトリルのようなアクリル系樹脂における表面官能基（ニトリル基）とチタン含有金属酸化物の表面との相互作用が強いためと予想される。このような結着剤を用いた場合いは、前述したような負極を作製する際の不具合が生じ易い。そのため、ニトリル基を含むアクリル系樹脂を主体とした結着剤を用いている場合には、実施形態の構成を採用することでより顕著に効果が現れることが期待できる。 As the acrylic resin (acrylic polymer), those mainly composed of an acrylic resin containing a nitrile group are preferable. Specific examples include those mainly composed of polyacrylonitrile. Such a binder has a particularly strong interaction with the titanium-containing metal oxide that is the negative electrode active material. This is presumably due to the strong interaction between the surface functional group (nitrile group) in the acrylic resin such as polyacrylonitrile and the surface of the titanium-containing metal oxide. When such a binder is used, the above-described problems in producing the negative electrode are likely to occur. Therefore, when a binder mainly composed of an acrylic resin containing a nitrile group is used, it can be expected that a more remarkable effect can be expected by adopting the configuration of the embodiment.
　結着剤として、２種以上のアクリル系樹脂を混合して用いても良い。また、アクリル系樹脂以外の結着剤を１種以上含んでもよい。 As a binder, two or more kinds of acrylic resins may be mixed and used. Moreover, you may contain 1 or more types of binders other than acrylic resin.
　アクリル系樹脂以外の結着剤の例は、ポリフッ化ビニリデン(polyvinylidene fluoride；ＰＶｄＦ）、その他のフッ素系ゴム、ポリプロピレン(polypropylene；ＰＰ)、ポリエチレン(polyethylene；ＰＥ）、カルボキシメチルセルロース(carboxymethyl cellulose；ＣＭＣ)、ポリイミド(polyimide；ＰＩ)、ポリアミドイミド(polyamidemide；ＰＡＩ)等を挙げることができる。 Examples of binders other than acrylic resins are polyvinylidene fluoride (PVdF), other fluororubbers, polypropylene (PP), polyethylene (polyethylene; PE), carboxymethyl cellulose (CMC). , Polyimide (PI), polyamidemide (PAI), and the like.
　アクリル系樹脂以外の結着剤の割合は、負極に含まれている全ての結着剤の３０重量％以下であることが好ましい。さらに好ましくは、アクリル系樹脂以外の結着剤の割合は１０重量％以下である。 The ratio of the binder other than the acrylic resin is preferably 30% by weight or less of all the binders included in the negative electrode. More preferably, the ratio of the binder other than the acrylic resin is 10% by weight or less.
　負極活物質、導電剤及び結着剤の配合比は、以下のとおりが好ましい。負極活物質の配合比は７０質量％以上９６質量％以下の範囲であることが好ましい。負極導電剤の配合比は２質量％以上２８質量％以下の範囲であることが好ましい。結着剤の配合比は２質量％以上２８質量％以下の範囲であることが好ましい。 The compounding ratio of the negative electrode active material, the conductive agent and the binder is preferably as follows. The compounding ratio of the negative electrode active material is preferably in the range of 70% by mass to 96% by mass. The compounding ratio of the negative electrode conductive agent is preferably in the range of 2% by mass to 28% by mass. The blending ratio of the binder is preferably in the range of 2% by mass to 28% by mass.
　導電剤が２質量％未満であると、負極合剤層の集電性能が低下し、非水電解質二次電池の大電流性能が低下する恐れがある。また、結着剤が２質量％未満であると、負極合剤層と負極集電体との結着性が低下し、その結果抵抗が増大してサイクル性能が低下する恐れがある。一方、高容量化の観点から、導電剤及び結着剤は各々２８質量％以下であることが好ましい。 When the conductive agent is less than 2% by mass, the current collecting performance of the negative electrode mixture layer is lowered, and the large current performance of the nonaqueous electrolyte secondary battery may be lowered. On the other hand, when the binder is less than 2% by mass, the binding property between the negative electrode mixture layer and the negative electrode current collector is lowered, and as a result, the resistance is increased and the cycle performance may be lowered. On the other hand, from the viewpoint of increasing the capacity, the conductive agent and the binder are each preferably 28% by mass or less.
　負極合剤層の単位面積当たりの重量は、１０ｇ／ｍ２以上１６０ｇ／ｍ２以下であることが好ましい。ここで負極合剤層の単位面積当たりの重量とは、負極集電体の両面に負極合剤層が塗布されている場合は、どちらか片面当たりの負極合剤層の面積を指す。単位面積当たりの重量が１０ｇ／ｍ２未満である負極合剤層の作製は、量産プロセスに適さない。また、負極合剤層の単位面積当たりの重量が１６０ｇ／ｍ２を超えると負極作製に支障をきたしやすい。より好ましい負極合剤層の単位面積当たりの重量の範囲は、２５ｇ／ｍ２から１４０ｇ／ｍ２以下である。 The weight per unit area of the negative electrode mixture layer is preferably 10 g / m 2 or more and 160 g / m 2 or less. Here, the weight per unit area of the negative electrode mixture layer refers to the area of the negative electrode mixture layer per one side when the negative electrode mixture layer is applied to both surfaces of the negative electrode current collector. Production of a negative electrode mixture layer having a weight per unit area of less than 10 g / m 2 is not suitable for a mass production process. Moreover, when the weight per unit area of the negative electrode mixture layer exceeds 160 g / m 2 , the negative electrode production is likely to be hindered. A more preferable range of the weight per unit area of the negative electrode mixture layer is 25 g / m 2 to 140 g / m 2 .
　負極集電体上に配置されている負極合剤層は、集電体の片面あたりの厚さが１０μｍ以上１００μｍ以下であることが好ましい。より好ましい厚さの範囲は、１５μｍ以上７５μｍ以下である。 The negative electrode mixture layer disposed on the negative electrode current collector preferably has a thickness of 10 μm to 100 μm per side of the current collector. A more preferable thickness range is 15 μm or more and 75 μm or less.
　負極集電体として、導電性の箔を用いることができる。このような集電体としては、例えば金属箔や合金製の箔がある。負極集電体としてアルミニウム箔またはアルミニウム合金箔を用いることが好ましい。アルミニウム箔およびアルミニウム合金箔の厚さは、２０μｍ以下であることが好ましく、１５μｍ以下であることがより好ましい。これにより、負極の強度を保ちながら軽量化できる。アルミニウム箔の純度は９９重量％以上が好ましい。アルミニウム合金としては、Ｍｇ、Ｚｎ、Ｓｉなどの元素を含む合金が好ましい。一方、Ｆｅ、Ｃｕ、Ｎｉ、Ｃｒなどの遷移元素を含む場合、その含有量は１重量％以下であることが好ましい。 As the negative electrode current collector, a conductive foil can be used. Examples of such a current collector include a metal foil and an alloy foil. It is preferable to use an aluminum foil or an aluminum alloy foil as the negative electrode current collector. The thickness of the aluminum foil and aluminum alloy foil is preferably 20 μm or less, and more preferably 15 μm or less. Thereby, it can reduce in weight, maintaining the intensity | strength of a negative electrode. The purity of the aluminum foil is preferably 99% by weight or more. As the aluminum alloy, an alloy containing an element such as Mg, Zn, or Si is preferable. On the other hand, when a transition element such as Fe, Cu, Ni, or Cr is included, the content is preferably 1% by weight or less.
　負極集電体の表面には、アンダーコート層がさらに形成されていることがより好ましい。表面にアンダーコート層が形成された金属箔を集電体として用いた場合には、負極合剤層の形成のためのスラリーに対する集電体表面の濡れ性が改善される。こうすることで、負極集電体と負極合剤層との密着性をさらに改善することができる。これは、アルミニウム箔からスラリーが弾いてしまう、いわゆるハジキ現象が生じることを抑制したり、集電体と合剤層との剥離強度が低下することを防いだりすることができるためである。つまり、集電体の表面にアンダーコート層を形成することで、上述した負極作製の際の不具合をよりよく抑えることができ、それにより負極集電体と負極合剤層との密着性を改善することができる。 More preferably, an undercoat layer is further formed on the surface of the negative electrode current collector. When a metal foil having an undercoat layer formed on the surface is used as a current collector, the wettability of the current collector surface with respect to the slurry for forming the negative electrode mixture layer is improved. By carrying out like this, the adhesiveness of a negative electrode collector and a negative mix layer can further be improved. This is because it is possible to suppress the so-called repelling phenomenon that the slurry repels from the aluminum foil, and to prevent the peel strength between the current collector and the mixture layer from being lowered. In other words, by forming the undercoat layer on the surface of the current collector, the above-described problems during the production of the negative electrode can be better suppressed, thereby improving the adhesion between the negative electrode current collector and the negative electrode mixture layer. can do.
　結着剤としてアクリル系樹脂を用い、集電体として例えばアルミニウム箔を用いた場合に、この集電体の表面にアンダーコート層が形成されていないと、上述したように結着剤が活物質同士を優先的に結着させてしまうことがある。これは、活物質表面と結着剤の表面官能基との相互作用によるものと予想される。集電体表面にアンダーコート層を形成することで、このように活物質とアクリル系樹脂との相互作用により結着剤が活物質同士の結着に優先的に使用されることを回避することができる。そのため、より高い確率で、集電体と合剤層との密着性に優れた負極を作製することができる。 When an acrylic resin is used as the binder and, for example, an aluminum foil is used as the current collector, if the undercoat layer is not formed on the surface of the current collector, the binder is the active material as described above. There are cases where they are bound preferentially. This is expected to be due to the interaction between the active material surface and the surface functional group of the binder. By forming an undercoat layer on the current collector surface, it is possible to avoid the binder being used preferentially for the binding between the active materials due to the interaction between the active material and the acrylic resin. Can do. Therefore, a negative electrode excellent in the adhesion between the current collector and the mixture layer can be produced with higher probability.
　負極集電体の表面に形成するアンダーコート層は、炭素材料を含み、集電体の片面当たりの厚さが２μｍ以下であることが好ましい。アンダーコート層に含まれる炭素材料としては、グラファイト（黒鉛）、アセチレンブラック、カーボンブラックなどを用いることができる。また、前記アンダーコート層は、樹脂を含んでいても良い。 The undercoat layer formed on the surface of the negative electrode current collector preferably contains a carbon material, and the thickness per side of the current collector is preferably 2 μm or less. As the carbon material contained in the undercoat layer, graphite (graphite), acetylene black, carbon black and the like can be used. The undercoat layer may contain a resin.
　また、アンダーコート層は、樹脂を含み得る。アンダーコート層に含まれる樹脂としては、フッ素系樹脂（ＰＶｄＦなど）、ポリアクリル酸、アクリル系樹脂、ポリオレフィン樹脂、ポリイミド(polyimide；ＰＩ)、ポリアミド(polyamide；ＰＡ)、ポリアミドイミド(polyamidemide；ＰＡＩ)等を挙げることができる。アンダーコート層に含まれる樹脂としては、アクリル系樹脂が好ましい。これは、アンダーコート層中にアクリル樹脂を含ませることで、アンダーコート層と負極合剤層に含まれる結着剤としてのアクリル系樹脂との親和性が優れたものになるためである。 Further, the undercoat layer can contain a resin. Resins contained in the undercoat layer include fluorine resins (such as PVdF), polyacrylic acid, acrylic resins, polyolefin resins, polyimide (PI), polyamide (polyamide), and polyamideimide (PAI). Etc. As the resin contained in the undercoat layer, an acrylic resin is preferable. This is because by including an acrylic resin in the undercoat layer, the affinity between the undercoat layer and the acrylic resin as the binder contained in the negative electrode mixture layer becomes excellent.
　第１の実施形態に係る非水電解質二次電池の含む負極は、例えば次の方法により作製することができる。まず、負極活物質、導電剤及び結着剤を溶媒に懸濁してスラリーを調製する。このスラリーを、負極集電体の片面又は両面に塗布する。次いで、塗布したスラリーを乾燥して、負極合剤層を形成する。その後、集電体と負極合剤層とにプレスを施す。ここで、負極の製造方法の条件を制御することによって、負極における剥離強度αと切削強度βとの比（α／β）を適切な値にすることにできる。 The negative electrode included in the nonaqueous electrolyte secondary battery according to the first embodiment can be produced by, for example, the following method. First, a negative electrode active material, a conductive agent, and a binder are suspended in a solvent to prepare a slurry. This slurry is applied to one side or both sides of the negative electrode current collector. Next, the applied slurry is dried to form a negative electrode mixture layer. Thereafter, the current collector and the negative electrode mixture layer are pressed. Here, by controlling the conditions of the negative electrode manufacturing method, the ratio (α / β) of the peel strength α and the cutting strength β in the negative electrode can be set to an appropriate value.
　負極合剤層と負極集電体との剥離強度αは、当然負極合剤層に用いる活物質や結着剤等の材料種によって変化し得るが、負極の製造条件による影響も受ける。後述するように、負極の製造において、負極活物質と導電剤と結着剤とを含んだスラリーを負極集電体上に塗布するが、このときのスラリーの塗工速度や塗膜の厚さによって剥離強度αが変化し得る。例えば、塗工速度を低下させた結果、剥離強度αが増加し得る。また、負極集電体上に塗布した上記スラリーを乾燥させることで負極合剤層が形成されるが、このときの乾燥温度によっても、剥離強度αが変化し得る。 The peel strength α between the negative electrode mixture layer and the negative electrode current collector can naturally vary depending on the type of material such as the active material and binder used in the negative electrode mixture layer, but is also affected by the manufacturing conditions of the negative electrode. As will be described later, in the production of the negative electrode, a slurry containing a negative electrode active material, a conductive agent, and a binder is applied on the negative electrode current collector. At this time, the slurry coating speed and the thickness of the coating film are applied. Can change the peel strength α. For example, as a result of reducing the coating speed, the peel strength α can be increased. Moreover, although the negative mix layer is formed by drying the said slurry apply | coated on the negative electrode electrical power collector, peeling strength (alpha) may change also with the drying temperature at this time.
　上記切削強度βは、剥離強度αと同様に、負極合剤層に用いる活物質や結着剤等の材料種によって変化し得るとともに、負極の製造条件による影響も受ける。切削強度βは、負極集電体上へ塗布するスラリーの厚さによって変化し得る。また、後述するように負極の製造において、集電体とその上に形成された負極合剤層とにプレスを施すが、この時のプレス温度、即ちプレスに用いるロールの温度によっても切削強度βが変化し得る。 The cutting strength β can vary depending on the type of material such as an active material and a binder used for the negative electrode mixture layer, and is also affected by the manufacturing conditions of the negative electrode, similarly to the peel strength α. The cutting strength β can vary depending on the thickness of the slurry applied on the negative electrode current collector. As will be described later, in the production of the negative electrode, the current collector and the negative electrode mixture layer formed thereon are pressed, and the cutting strength β depends on the pressing temperature at this time, that is, the temperature of the roll used in the pressing. Can change.
　集電体上にアンダーコート層を形成する場合には、特に限定されないが、例えば次のような方法を用いることができる。先ず、上述した樹脂を溶剤に溶解させた溶液に、グラファイト、アセチレンブラックなどの炭素材料を混合して塗料を作製する。集電体とするアルミニウム箔上にこの塗料を塗布し、次いで乾燥することによって、表面にアンダーコート層が形成された集電体を作製することができる。この集電体を用いて、アンダーコート層が形成された面（片面又は両面）に負極活物質と導電剤と結着剤とを含んだスラリーを塗布し、上述したと同様の方法で負極を作製することができる。 When the undercoat layer is formed on the current collector, it is not particularly limited, but for example, the following method can be used. First, a coating material is prepared by mixing a carbon material such as graphite or acetylene black in a solution obtained by dissolving the above-described resin in a solvent. A current collector having an undercoat layer formed on the surface can be produced by applying this paint on an aluminum foil serving as a current collector and then drying the paint. Using this current collector, a slurry containing a negative electrode active material, a conductive agent and a binder was applied to the surface (one side or both sides) on which the undercoat layer was formed, and the negative electrode was formed in the same manner as described above. Can be produced.
　負極における集電体と負極合剤層との剥離強度αは、電極剥離強度測定装置（レオメータ）を用いて測定することができる。測定方法を次に示す。まず、試験対象の負極を２×５ｃｍの短冊状に切り出したものを測定サンプルとする。次に、各測定用サンプルの負極合剤層の表面にテープを貼る。ここで用いるテープとしては、例えば３Ｍ社製スコッチ（登録商標）両面テープ665（巻芯径25mm）を用いることができる。そのテープを電極剥離強度測定装置にかけることにより、負極集電体から負極合剤層を１８０度の剥離角度で、２ｃｍ／ｍｉｎの剥離速度で剥離する。負極合剤層が負極集電体から２ｃｍ剥離した時点で、負極合剤層の剥離に必要とした力を記録し、適切な単位に換算して剥離強度（Ｎ／ｍ）とする。ここで、適切な単位に換算するとは、次に説明する表面・界面切削法により測定される切削強度と同じ単位となるように換算することを示す。 The peel strength α between the current collector and the negative electrode mixture layer in the negative electrode can be measured using an electrode peel strength measuring device (rheometer). The measurement method is as follows. First, a measurement sample is obtained by cutting a negative electrode to be tested into a 2 × 5 cm strip shape. Next, a tape is stuck on the surface of the negative electrode mixture layer of each measurement sample. As the tape used here, for example, Scotch (registered trademark) double-sided tape 665 (winding core diameter: 25 mm) manufactured by 3M can be used. By applying the tape to an electrode peel strength measuring device, the negative electrode mixture layer is peeled from the negative electrode current collector at a peel angle of 180 ° and a peel rate of 2 cm / min. When the negative electrode mixture layer peels 2 cm from the negative electrode current collector, the force required for peeling the negative electrode mixture layer is recorded, and converted to an appropriate unit to obtain the peel strength (N / m). Here, the conversion to an appropriate unit indicates that the conversion is performed so that the unit is the same as the cutting strength measured by the surface / interface cutting method described below.
　負極合剤層における切削強度βは、表面・界面切削法によって測定することができる。表面・界面切削法は、微細で鋭利な切り刃を用い、試料表面に対する刃の深さ位置を制御しつつ水平方向への切削を行い、この刃にかかる応力を計測する手法である。具体的には、刃の深さ位置を、負極合剤層内の所定の深さに固定しながら切削を行う事により、負極合剤層内の切削強度を測定することができる。この時、集電体の長さ方向(水平方向)に一定の所要の速度で切削を行う。その際、負極合剤層内を切削することで切り刃の先端が受ける応力から、負極合剤層における切削強度β（Ｎ／ｍ）が求められる。 The cutting strength β in the negative electrode mixture layer can be measured by a surface / interface cutting method. The surface / interface cutting method uses a fine and sharp cutting blade, performs cutting in the horizontal direction while controlling the depth position of the blade with respect to the sample surface, and measures the stress applied to the blade. Specifically, the cutting strength in the negative electrode mixture layer can be measured by performing cutting while fixing the depth position of the blade to a predetermined depth in the negative electrode mixture layer. At this time, cutting is performed at a constant required speed in the length direction (horizontal direction) of the current collector. At that time, the cutting strength β (N / m) in the negative electrode mixture layer is obtained from the stress received by the tip of the cutting blade by cutting the inside of the negative electrode mixture layer.
　表面・界面切削法による切削強度の測定は、サイカス(Surface And Interfacial Cutting Analysis System；ＳＡＩＣＡＳ）（登録商標）のような切削強度測定装置を用いて行うことができる。なお、表面・界面切削法は、ＳＡＩＣＡＳ法と称されることもある。切り刃には、刃幅が１．０ｍｍのボラゾン材質のセラミック刃を使用する。刃角は、すくい角度２０度、にげ角度１０度とする。測定においてはまず、水平速度２μｍ／秒、垂直速度０．２μｍ／秒の一定速度で切削を行うことで、負極合剤層内の所定の深さまで刃を移動させる。負極表面から６μm深さに到達した後、垂直方向の切削を停止し、水平速度２μｍ／秒の定速度モードにより切削強度測定を行う。なお、測定温度は室温、試料温度の何れも室温（２５℃）とする。 The measurement of the cutting strength by the surface / interface cutting method can be performed by using a cutting strength measuring device such as a surface-and-interfacial-cutting-analysis system (SAICAS) (registered trademark). The surface / interface cutting method may be referred to as the SAICAS method. As the cutting blade, a ceramic blade made of borazon material having a blade width of 1.0 mm is used. The blade angle is a rake angle of 20 degrees and a bald angle of 10 degrees. In the measurement, first, the blade is moved to a predetermined depth in the negative electrode mixture layer by cutting at a constant speed of 2 μm / second in horizontal speed and 0.2 μm / second in vertical speed. After reaching 6 μm depth from the negative electrode surface, cutting in the vertical direction is stopped, and cutting strength is measured in a constant speed mode with a horizontal speed of 2 μm / sec. The measurement temperature is room temperature and the sample temperature is room temperature (25 ° C.).
　負極合剤層内における結着剤としてのアクリル系樹脂の存在は、赤外吸収スペクトル(infra-red spectroscopy；ＩＲ)分析、または熱分解ガスクロマトグラフィー(pyrolysis-gas chromatography-mass/spectrometry；Ｐｙ－ＧＣ／ＭＳ)によって確認することができる。 The presence of acrylic resin as a binder in the negative electrode mixture layer is determined by infrared absorption spectrum (IR) analysis or pyrolysis-gas chromatography (mass / spectrometry; Py-). GC / MS).
　赤外吸収スペクトル(ＩＲ)測定を用いる場合は、例えば次のような手順にて負極合剤層内の結着剤の成分を確認することができる。まず、完全放電状態とした電池を、アルゴンを充填したグローブボックス中で分解する。ここで、完全放電状態とは、充電状態(state of charge；ＳＯＣ)が０％の状態のことを意味する。分解した電池から、測定対象の負極を取り出す。この負極を適切な溶媒で洗浄する。洗浄に用いる溶媒としては、例えばエチルメチルカーボネートなどを用いると良い。洗浄後の負極を、例えば、Ｎ－メチル－２－ピロリドン(N-methyl-2-pyrrolidone；ＮＭＰ)、ジメチルホルムアミド(dimethylformamide；ＤＭＦ)等の有機溶媒に浸漬し、超音波振動を加えることによって、負極合剤層から結着剤樹脂を抽出する。その後、抽出溶媒から固形分を濾過し、得られた濾液を、鏡面処理をした金属板の上に流し落とす。そして、金属板の上で、抽出溶媒の濾液を加熱乾燥する。 When using infrared absorption spectrum (IR) measurement, for example, the components of the binder in the negative electrode mixture layer can be confirmed by the following procedure. First, a fully discharged battery is disassembled in a glove box filled with argon. Here, the completely discharged state means that the state of charge (SOC) is 0%. The negative electrode to be measured is taken out from the disassembled battery. This negative electrode is washed with a suitable solvent. As a solvent used for washing, for example, ethyl methyl carbonate may be used. By immersing the cleaned negative electrode in an organic solvent such as N-methyl-2-pyrrolidone (NMP) or dimethylformamide (DMF) and applying ultrasonic vibration, The binder resin is extracted from the negative electrode mixture layer. Thereafter, the solid content is filtered from the extraction solvent, and the obtained filtrate is poured onto a mirror-treated metal plate. And the filtrate of an extraction solvent is heat-dried on a metal plate.
　溶媒を乾燥させた後、残留した固形分に対し、例えば反射測定法にてＩＲ測定を行う。ＩＲ測定装置としては、例えば日本分光株式会社製　ＦＴ/ＩＲ-６１００　ＤＴＧＳ検出器を用いることができる。このようにして得られたデータを解析することにより、負極合剤層内におけるアクリル系樹脂の存在を確認することができる。 After drying the solvent, IR measurement is performed on the remaining solid content by, for example, a reflection measurement method. As the IR measuring device, for example, FT / IR-6100 DTGS detector manufactured by JASCO Corporation can be used. By analyzing the data thus obtained, the presence of the acrylic resin in the negative electrode mixture layer can be confirmed.
　また、熱分解ガスクロマトグラフィー(pyrolysis-gas chromatography/mass spectrometry；Ｐｙ－ＧＣ／ＭＳ)を用いる場合は、例えば次のような手順にて負極合剤層中の結着剤の成分を確認できる。ＩＲ測定を用いる場合と同様にして、分解した電池から負極を取り出し、洗浄する。洗浄後の負極から、へら（箆）状の道具を用いて負極合剤層を剥がし取る。このとき、負極集電体が混入しないように注意する。剥がし取った合剤層を測定ホルダーにセットし、測定する。なお、測定ホルダーとしては、表面を不活性処理したステンレス製試料カップが好ましい。試料量としては１ｍｇ程度が好ましい。 In the case of using pyrolysis-gas chromatography / mass spectrometry (Py-GC / MS), for example, the components of the binder in the negative electrode mixture layer can be confirmed by the following procedure. In the same manner as in the case of using IR measurement, the negative electrode is taken out from the decomposed battery and washed. The negative electrode mixture layer is peeled off from the washed negative electrode using a spatula-like tool. At this time, care should be taken not to mix the negative electrode current collector. The peeled mixture layer is set in a measurement holder and measured. As the measurement holder, a stainless steel sample cup whose surface is subjected to an inert treatment is preferable. The sample amount is preferably about 1 mg.
　Ｐｙ－ＧＣ／ＭＳ測定装置としては、例えばＰｙ（パイロライザー）：フロンティア・ラボ株式会社製ＰＹ－２０２０ｉｄと、これを接続したＧＳ/ＭＳ：アジレント・テクノロジー株式会社製７８９０ＧＣ／５９７５ＣＭＳＤとを用いることができる。この装置では、自動サンプラーを用いて熱分解装置の炉心に試料を自動落下させることができる。この場合、熱分解温度を６００℃として測定することが好ましい。試料の分解は、５０ｍｌ/分のヘリウムキャリアーガス気流中で行い、生成物を５０：１のスプリッターを介してオンラインでＧＣ/ＭＳへと導入する。この際、熱分解装置とＧＣ/ＭＳを接続するインターフェース部、およびＧＣ/ＭＳの試料導入部の温度は、３２０℃とする。分離カラムとしては、無極性カラム、例えば、無極性の化学結合型ポリ（５％フェニル）メチルシロキサンを固定相（膜厚０．２５％μｍ）とする分離カラムを用いることができる。分離した生成物の検出は、直結されている四重極型質量分析計により行う。このようにして得られたデータを解析することにより負極合剤層内におけるアクリル系樹脂の存在を確認することができる。 As the Py-GC / MS measuring device, for example, Py (Pyrolyzer): PY-2020id manufactured by Frontier Laboratories, and GS / MS connected thereto: 7890GC / 5975CMSD manufactured by Agilent Technology Co., Ltd. may be used. it can. In this apparatus, an automatic sampler can be used to automatically drop a sample into the core of the thermal decomposition apparatus. In this case, it is preferable to measure at a thermal decomposition temperature of 600 ° C. Sample degradation occurs in a helium carrier gas stream at 50 ml / min and the product is introduced online into the GC / MS via a 50: 1 splitter. At this time, the temperature of the interface unit connecting the pyrolyzer and the GC / MS and the sample introducing unit of the GC / MS are set to 320 ° C. As the separation column, a nonpolar column, for example, a separation column using a non-polar chemically bonded poly (5% phenyl) methylsiloxane as a stationary phase (film thickness: 0.25% μm) can be used. The separated product is detected by a directly connected quadrupole mass spectrometer. The presence of the acrylic resin in the negative electrode mixture layer can be confirmed by analyzing the data thus obtained.
　負極集電体の表面におけるアンダーコート層の有無は、負極の断面を走査型電子顕微鏡（scanning electron microscope；ＳＥＭ）観察およびＥＤＸによる元素分析(energy dispersive X-ray spectroscopy；ＥＤＸ)を行うことにより確認することができる。まず、完全放電状態（ＳＯＣ０％）とした電池を、アルゴンを充填したグローブボックス中で分解する。分解した電池から、測定対象のアンダーコート層を含む負極を取り出す。この負極を適切な溶媒で洗浄する。洗浄に用いる溶媒としては、例えばエチルメチルカーボネートなどを用いると良い。洗浄が不十分であると、負極中に残留した炭酸リチウムやフッ化リチウムなどの影響により、アンダーコート層を観察しにくくなる場合がある。 The presence or absence of an undercoat layer on the surface of the negative electrode current collector was confirmed by observing the cross section of the negative electrode with a scanning electron microscope (SEM) and elemental analysis (energy X-ray X-ray spectrocopy: EDX). can do. First, a battery in a completely discharged state (SOC 0%) is disassembled in a glove box filled with argon. The negative electrode including the undercoat layer to be measured is taken out from the decomposed battery. This negative electrode is washed with a suitable solvent. As a solvent used for washing, for example, ethyl methyl carbonate may be used. Insufficient cleaning may make it difficult to observe the undercoat layer due to the influence of lithium carbonate, lithium fluoride, etc. remaining in the negative electrode.
　このようにして取り出した負極の断面を、イオンミリング装置にて切り出す。切り出した負極の断面を、ＳＥＭ試料台に貼り付ける。このとき、負極が試料台から剥がれたり浮いたりしないように、導電性テープなどを用いて処理を施す。ＳＥＭ試料台に貼り付けた負極を、走査型電子顕微鏡(ＳＥＭ)にて観察する。ＳＥＭ測定時にも負極を不活性雰囲気に維持した状態で試料室に導入することが好ましい。 The cross section of the negative electrode taken out in this way is cut out with an ion milling device. The cross section of the cut-out negative electrode is attached to the SEM sample stage. At this time, treatment is performed using a conductive tape or the like so that the negative electrode does not peel off or float from the sample stage. The negative electrode attached to the SEM sample stage is observed with a scanning electron microscope (SEM). It is preferable that the negative electrode be introduced into the sample chamber while maintaining the inert atmosphere during SEM measurement.
　なお、ＳＥＭ観察において、負極集電体の表面におけるアンダーコート層の有無を確認しにくい場合は、ＥＤＸによる元素マッピングを行うことで、アンダーコート層の有無を確認することができる。ＳＥＭ－ＥＤＸ分析を行うことにより、どのような元素がどこに分布しているかを可視化できるので、負極集電体表面におけるアンダーコート層の有無をより詳細に確認することができる。 In addition, in SEM observation, when it is difficult to confirm the presence or absence of the undercoat layer on the surface of the negative electrode current collector, the presence or absence of the undercoat layer can be confirmed by performing element mapping by EDX. By performing SEM-EDX analysis, it is possible to visualize what elements are distributed where, so that the presence or absence of an undercoat layer on the surface of the negative electrode current collector can be confirmed in more detail.
　（正極）
　正極は、正極集電体及び正極活物質層（正極合剤層）を含む。正極合剤層は、正極活物質、導電剤及び結着剤を含む。正極合剤層は、正極集電体の片面若しくは両面に形成される。 (Positive electrode)
The positive electrode includes a positive electrode current collector and a positive electrode active material layer (positive electrode mixture layer). The positive electrode mixture layer includes a positive electrode active material, a conductive agent, and a binder. The positive electrode mixture layer is formed on one side or both sides of the positive electrode current collector.
　正極活物質としてはリチウムを吸蔵する二酸化マンガン(ＭｎＯ２)、酸化鉄、酸化銅、酸化ニッケル、リチウムマンガン複合酸化物（例えば、LixMn2O4又はLixMnO2）、リチウムニッケル複合酸化物（例えば、LixNiO2）、リチウムコバルト複合酸化物（例えば、LixCoO2）、リチウムニッケルコバルト複合酸化物（例えば、LiNi1-yCoyO2）、リチウムマンガンコバルト複合酸化物（例えば、LixMnyCo1-yO2）、リチウムニッケルコバルトマンガン複合酸化物（例えば、LiNi1-y-zCoyMnzO2）、リチウムニッケルコバルトアルミニウム複合酸化物（例えば、LiNi1-y-zCoyAlzO2）、スピネル構造を有するリチウムマンガンニッケル複合酸化物（例えば、LixMn2-yNiyO4）、オリビン構造を有するリチウムリン酸化物（例えば、LixFePO4、LixMnPO4、LixMn1-yFeyPO4、LixCoPO4）、硫酸鉄（Fe2(SO4)3）、及びバナジウム酸化物（例えば、V2O5）が含まれる。上記において、０＜ｘ≦１であり、０≦ｙ≦１であり、０≦z≦１であることが好ましい。活物質として、これらの化合物を単独で用いてもよく、或いは、複数の化合物を組合せて用いてもよい。 As the positive electrode active material, manganese dioxide (MnO 2 ) that absorbs lithium, iron oxide, copper oxide, nickel oxide, lithium manganese composite oxide (for example, Li x Mn 2 O 4 or Li x MnO 2 ), lithium nickel composite oxide (Eg, Li x NiO 2 ), lithium cobalt composite oxide (eg, Li x CoO 2 ), lithium nickel cobalt composite oxide (eg, LiNi 1-y Co y O 2 ), lithium manganese cobalt composite oxide ( For example, Li x Mn y Co 1- y O 2), lithium-nickel-cobalt-manganese composite oxide (e.g., LiNi 1-yz Co y Mn z O 2), lithium-nickel-cobalt-aluminum composite oxide (e.g., LiNi 1-yz Co y Al z O 2 ), lithium manganese nickel composite oxide having a spinel structure (eg, Li x Mn 2 -y Ni y O 4 ), lithium phosphorous oxide having an olivine structure (eg, Li x FePO 4 , Li x MnPO 4 Li x Mn 1-y Fe y PO 4, Li x CoPO 4), iron sulfate (Fe 2 (SO 4) 3 ), and vanadium oxides (e.g., V 2 O 5) include. In the above, 0 <x ≦ 1, 0 ≦ y ≦ 1, and 0 ≦ z ≦ 1 are preferable. As the active material, these compounds may be used alone, or a plurality of compounds may be used in combination.
　中でもリチウムマンガン複合酸化物（LixMn2O4）、リチウムコバルト複合酸化物（LixCoO2）、リチウムニッケルコバルト複合酸化物（LixNi1-yCoyO2）、リチウムマンガンコバルト複合酸化物（LixMnyCo1-yO2）、リチウムニッケルコバルトマンガン複合酸化物（例えばLiNi1-y-zCoyMnzO2）、オリビン構造を有するリチウムリン酸化物（例えば、LixFePO4、LixMnPO4、LixMn1-yFeyPO4、LixCoPO4）が好ましい。上記において、０＜ｘ≦１であり、０≦ｙ≦１であり、０≦ｚ≦１であることが好ましい。 Among them, lithium manganese composite oxide (Li x Mn 2 O 4 ), lithium cobalt composite oxide (Li x CoO 2 ), lithium nickel cobalt composite oxide (Li x Ni 1-y CoyO 2 ), lithium manganese cobalt composite oxide (Li x Mn y Co 1- y O 2), lithium-nickel-cobalt-manganese composite oxide (e.g., LiNi 1-yz Co y Mn z O 2), lithium phosphates having an olivine structure (e.g., Li x FePO 4, Li x MnPO 4 , Li x Mn 1-y Fe y PO 4 , Li x CoPO 4 ) are preferred. In the above, 0 <x ≦ 1, 0 ≦ y ≦ 1, and 0 ≦ z ≦ 1 are preferable.
　導電剤の例には、アセチレンブラック、カーボンブラック、黒鉛、カーボンナノファイバー、及びカーボンナノチューブのような炭素質物が含まれる。これらの炭素質物を単独で用いてもよいし、或いは複数の炭素質物を用いてもよい。 Examples of the conductive agent include carbonaceous materials such as acetylene black, carbon black, graphite, carbon nanofiber, and carbon nanotube. These carbonaceous materials may be used alone or a plurality of carbonaceous materials may be used.
　結着剤は、分散された正極活物質の間隙を埋め、正極活物質と導電剤を結着させ、また、正極活物質と正極集電体とを結着させる。 The binder fills the gap between the dispersed positive electrode active materials, binds the positive electrode active material and the conductive agent, and binds the positive electrode active material and the positive electrode current collector.
　結着剤としては、例えば、ポリテトラフルオロエチレン(polytetrafluoroethylene;ＰＴＦＥ)、ポリフッ化ビニリデン(polyvinylidene fluoride;ＰＶｄＦ)、ポリフッ化ビニリデン変性体(ＰＶｄＦ変性体)、ポリイミド(polyimide；ＰＩ)、ポリアミドイミド(polyamideimide；ＰＡＩ)、アクリル系樹脂（アクリル系ポリマー）などが挙げられる。 Examples of the binder include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), a modified polyvinylidene fluoride (PVdF), a polyimide (polyimide), and a polyamideimide (polyamideimide). PAI), acrylic resins (acrylic polymers) and the like.
　中でも、アクリル系樹脂（アクリル系ポリマー）は、高温において電解液に対して膨潤しにくく、高温で充放電サイクルを繰り返しても正極の電子伝導のネットワークが維持される。そのため、結着剤としてアクリル系樹脂を用いた正極を含んだ電池では、高温でのセル抵抗の上昇が抑制され、電池の高温サイクル性能が向上するので、好ましい。 Among these, acrylic resins (acrylic polymers) are less likely to swell with respect to the electrolyte solution at high temperatures, and the electron conduction network of the positive electrode is maintained even after repeated charge / discharge cycles at high temperatures. Therefore, a battery including a positive electrode using an acrylic resin as a binder is preferable because an increase in cell resistance at high temperatures is suppressed and the high-temperature cycle performance of the battery is improved.
　アクリル系樹脂（アクリル系ポリマー）は、重合体または共重合体であってもよい。或いは、アクリル系樹脂は重合体および共重合体の両方を含んでいても良い。 The acrylic resin (acrylic polymer) may be a polymer or a copolymer. Alternatively, the acrylic resin may contain both a polymer and a copolymer.
　アクリル系樹脂（アクリル系ポリマー）を構成するモノマーの例には、アクリル基を有するモノマーおよびメタクリル基を有するモノマーが含まれる。アクリル基を有するモノマーは、典型的には、アクリル酸またはアクリル酸エステルである。メタクリル基を有するモノマーは、典型的には、メタクリル酸またはメタクリル酸エステルである。 Examples of the monomer constituting the acrylic resin (acrylic polymer) include a monomer having an acrylic group and a monomer having a methacryl group. The monomer having an acrylic group is typically acrylic acid or an acrylate ester. The monomer having a methacryl group is typically methacrylic acid or a methacrylic ester.
　アクリル系樹脂（アクリル系ポリマー）を構成するモノマーの例には、アクリル酸エチル、アクリル酸メチル、アクリル酸ブチル、アクリル酸２-エチルヘキシル、アクリル酸イソノニル、アクリル酸ヒドロキシエチル、メタクリル酸メチル、メタクリル酸グリシジル、アクリロニトリル、スチレン、およびアクリルアミドが含まれる。 Examples of monomers constituting the acrylic resin (acrylic polymer) include ethyl acrylate, methyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, isononyl acrylate, hydroxyethyl acrylate, methyl methacrylate, methacrylic acid Glycidyl, acrylonitrile, styrene, and acrylamide are included.
　アクリル系樹脂（アクリル系ポリマー）としては、ニトリル基を含むアクリル系樹脂を主体とするものが好ましい。具体的には、ポリアクリロニトリルを主体とするものが挙げられる。結着剤として、２種以上のアクリル系樹脂を混合して用いても良い。 As the acrylic resin (acrylic polymer), those mainly composed of an acrylic resin containing a nitrile group are preferable. Specific examples include those mainly composed of polyacrylonitrile. As the binder, two or more kinds of acrylic resins may be mixed and used.
　また、アクリル系樹脂以外の結着剤を１種以上含んでもよい。アクリル系樹脂以外の結着剤の例には、ポリフッ化ビニリデン(polyvinylidene fluoride；ＰＶｄＦ)、その他のフッ素系ゴム、ポリプロピレン(polypropylene；ＰＰ)、ポリエチレン(polyethylene；ＰＥ)、カルボキシメチルセルロース(carboxymethyl cellulose；ＣＭＣ)、ポリイミド(polyimide；ＰＩ)、ポリアミドイミド(polyamideimide；ＰＡＩ)等を挙げることができる。 Further, one or more binders other than acrylic resin may be included. Examples of binders other than acrylic resins include polyvinylidene fluoride (PVdF), other fluororubbers, polypropylene (PP), polyethylene (PE), carboxymethyl cellulose (CMC). ), Polyimide (PI), polyamideimide (PAI), and the like.
　アクリル系樹脂以外の結着剤の割合は、正極に含まれている全ての結着剤の３０重量％以下であることが好ましい。さらに好ましくは１０重量％以下である。 The ratio of the binder other than the acrylic resin is preferably 30% by weight or less of all the binders included in the positive electrode. More preferably, it is 10 weight% or less.
　正極層中の正極活物質、導電剤及び結着剤は、次の割合で配合することが好ましい。正極活物質は、８０質量％以上９５質量％以下の割合で配合することが好ましい。導電剤は、３質量％以上１８質量％以下の割合で配合することが好ましい。結着剤は、２質量％以上１７質量％以下の割合で配合することが好ましい。 The positive electrode active material, conductive agent and binder in the positive electrode layer are preferably blended in the following proportions. The positive electrode active material is preferably blended at a ratio of 80% by mass to 95% by mass. The conductive agent is preferably blended at a ratio of 3% by mass to 18% by mass. The binder is preferably blended at a ratio of 2% by mass to 17% by mass.
　導電剤の割合を３質量％以上の量にすることにより、高温で充放電サイクルを繰り返しても電子伝導のネットワークが維持される。そのため、高温でのセル抵抗の上昇が抑制される。また、導電剤の割合を１８質量％以下の量にすることにより、高温保存下での導電剤表面での非水電解質の分解を低減することができる。 By making the proportion of the conductive agent 3% by mass or more, an electronic conduction network is maintained even if the charge / discharge cycle is repeated at a high temperature. Therefore, an increase in cell resistance at high temperatures is suppressed. Moreover, by making the proportion of the conductive agent 18% by mass or less, decomposition of the nonaqueous electrolyte on the surface of the conductive agent under high temperature storage can be reduced.
　結着剤の割合を２質量％以上の量にすることにより十分な正極強度が得られる。結着剤の割合を１７質量％以下の量にすることにより、正極中では絶縁材料となる結着剤の配合量を減少させ、正極の内部抵抗を減少できる。 Sufficient positive electrode strength can be obtained by setting the ratio of the binder to 2% by mass or more. By setting the ratio of the binder to 17% by mass or less, the blending amount of the binder serving as an insulating material in the positive electrode can be reduced, and the internal resistance of the positive electrode can be reduced.
　正極集電体は、アルミニウム箔、またはＭｇ、ＺｎおよびＳｉから成る群より選択される１つ以上の元素を含むアルミニウム合金箔であることが好ましい。 The positive electrode current collector is preferably an aluminum foil or an aluminum alloy foil containing one or more elements selected from the group consisting of Mg, Zn and Si.
　アルミニウム箔およびアルミニウム合金箔の厚さは、２０μｍ以下であることが好ましく、１５μｍ以下であることがより好ましい。アルミニウム箔の純度は９９重量％以上であることが好ましい。Ｆｅ、Ｃｕ、Ｎｉ、Ｃｒなどの遷移金属を含有する場合、それらの含有量は１質量％以下であることが好ましい。 The thickness of the aluminum foil and the aluminum alloy foil is preferably 20 μm or less, and more preferably 15 μm or less. The purity of the aluminum foil is preferably 99% by weight or more. When transition metals such as Fe, Cu, Ni, and Cr are contained, their content is preferably 1% by mass or less.
　正極合剤層の密度は、３ｇ／ｃｍ３以上であることが好ましい。 The density of the positive electrode mixture layer is preferably 3 g / cm 3 or more.
　正極は、例えば次の方法により作製することができる。正極活物質、結着剤および導電剤を適切な溶媒に懸濁してスラリーを調製する。このスラリーを正極集電体の表面に塗布する。次いで、塗布したスラリーを乾燥して正極層を形成する。その後、正極集電体と正極層とにプレスを施す。結着剤を分散させるための有機溶媒としては、例えば、Ｎ－メチル－２－ピロリドン(Ｎ－methylpyrrolidone；ＮＭＰ)、ジメチルホルムアミド(dimethylformamide；ＤＭＦ)等が用いられる。正極はまた、正極活物質、結着剤および導電剤をペレット状に形成して正極層とし、これを正極集電体上に配置することにより作製されてもよい。 The positive electrode can be produced, for example, by the following method. A positive electrode active material, a binder, and a conductive agent are suspended in a suitable solvent to prepare a slurry. This slurry is applied to the surface of the positive electrode current collector. Next, the applied slurry is dried to form a positive electrode layer. Thereafter, the positive electrode current collector and the positive electrode layer are pressed. Examples of the organic solvent for dispersing the binder include N-methylpyrrolidone (NMP) and dimethylformamide (DMF). The positive electrode may also be produced by forming a positive electrode active material, a binder and a conductive agent into a pellet to form a positive electrode layer, which is disposed on the positive electrode current collector.
　（非水電解質）
　非水電解質としては、電解質を有機溶媒に溶解することにより調製される液状の有機電解質、液状の有機溶媒と高分子材料を複合化したゲル状の有機電解質、または、リチウム塩電解質と高分子材料を複合化した固体非水電解質が挙げられる。また、リチウムイオンを含有した常温溶融塩（イオン性融体）を非水電解質として用いてもよい。高分子材料としては、例えば、ポリフッ化ビニリデン(ＰＶｄＦ)、ポリアクリロニトリル(polyacrylonitrile；ＰＡＮ)、ポリエチレンオキサイド(polyethylene oxide；ＰＥＯ)等が挙げられる。 (Nonaqueous electrolyte)
Non-aqueous electrolytes include liquid organic electrolytes prepared by dissolving electrolytes in organic solvents, gelled organic electrolytes in which liquid organic solvents and polymer materials are combined, or lithium salt electrolytes and polymer materials And a solid non-aqueous electrolyte. Moreover, you may use the normal temperature molten salt (ionic melt) containing lithium ion as a non-aqueous electrolyte. Examples of the polymer material include polyvinylidene fluoride (PVdF), polyacrylonitrile (PAN), polyethylene oxide (PEO), and the like.
　非水電解質は、液状もしくはゲル状で、沸点が１００℃以上で、有機電解質または常温溶融塩を含有することが好ましい。 The non-aqueous electrolyte is preferably liquid or gel, has a boiling point of 100 ° C. or higher, and contains an organic electrolyte or a room temperature molten salt.
　液状の有機電解質は、電解質を０．５～２．５ｍｏｌ／Ｌの濃度で有機溶媒に溶解することにより、調製される。これにより、低温環境下においても高出力を取り出すことができる。有機電解質における電解質の濃度のより好ましい範囲は、１．５～２．５ｍｏｌ／Ｌの範囲である。なお、液状非水電解質は、非水電解液とも称することもある。 A liquid organic electrolyte is prepared by dissolving an electrolyte in an organic solvent at a concentration of 0.5 to 2.5 mol / L. Thereby, a high output can be taken out even in a low temperature environment. A more preferable range of the concentration of the electrolyte in the organic electrolyte is a range of 1.5 to 2.5 mol / L. Note that the liquid non-aqueous electrolyte may also be referred to as a non-aqueous electrolyte.
　電解質としては、例えば、四フッ化ホウ酸リチウム(ＬｉＢＦ４)、六フッ化リン酸リチウム(ＬｉＰＦ６)、六フッ化砒素リチウム(ＬｉＡｓＦ６)、過塩素酸リチウム(ＬｉＣｌＯ４)、トリフルオロメタンスルホン酸リチウム(ＬｉＣＦ３ＳＯ３)、ビストリフルオロメチルスルホニルイミドリチウム(ＬｉＮ(ＣＦ３ＳＯ２)２)、ビスペンタフルオロエチルスルホニルイミドリチウム(ＬｉＮ(Ｃ２Ｆ５ＳＯ２)２)、トリストリフルオロメチルスルホン酸リチウム(Ｌｉ(ＣＦ３ＳＯ２)３Ｃ)、リチウムオキサレートジフルオロボレート(ＬｉＢＦ２Ｃ２Ｏ４)、リチウムビスオキサレートボレート(ＬｉＢ[(ＯＣＯ)２]２)等が挙げられる。電解質の種類は、１種類または２種類以上にすることができる。これらの中でも、六フッ化リン酸リチウム(ＬｉＰＦ６)を含むものは、高電位においても酸化し難いため好ましい。 Examples of the electrolyte include lithium tetrafluoroborate (LiBF 4 ), lithium hexafluorophosphate (LiPF 6 ), lithium hexafluoroarsenide (LiAsF 6 ), lithium perchlorate (LiClO 4 ), and trifluoromethanesulfone. Lithium oxide (LiCF 3 SO 3 ), bistrifluoromethylsulfonylimide lithium (LiN (CF 3 SO 2 ) 2 ), bispentafluoroethylsulfonylimide lithium (LiN (C 2 F 5 SO 2 ) 2 ), tristrifluoromethyl Examples thereof include lithium sulfonate (Li (CF 3 SO 2 ) 3 C), lithium oxalate difluoroborate (LiBF 2 C 2 O 4 ), lithium bisoxalate borate (LiB [(OCO) 2 ] 2 ), and the like. The type of electrolyte can be one type or two or more types. Among these, those containing lithium hexafluorophosphate (LiPF 6 ) are preferable because they hardly oxidize even at a high potential.
　有機溶媒としては、例えば、プロピレンカーボネート(propylene carbonate；ＰＣ)やエチレンカーボネート(ethylene carbonate；ＥＣ)等の環状カーボネート、ジエチルカーボネート(diethyl carbonate；ＤＥＣ)やジメチルカーボネート(dimethyl carbonate；ＤＭＣ)あるいはメチルエチルカーボネート(methyl ethyl carbonate；ＭＥＣ)等の鎖状カーボネート、ジメトキシエタン(dimethoxyethane；ＤＭＥ)やジエトキシエタン(diethoxyethane；ＤＥＥ)等の鎖状エーテル、テトラヒドロフラン(tetrahydrofuran；ＴＨＦ)、ジオキソラン(dioxolane；ＤＯＸ)等の環状エーテル、γ－ブチロラクトン(gamma-butyrolactone；ＧＢＬ)、アセトニトリル(acetonitrile；ＡＮ)、スルホラン(sulfolane；ＳＬ)等が挙げられる。これらの有機溶媒は、単独または２種以上の混合物の形態で用いることができる。 Examples of the organic solvent include cyclic carbonates such as propylene carbonate (PC) and ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), and methyl ethyl carbonate. Chain carbonates such as (methyl ethyl carbonate (MEC)), chain ethers such as dimethoxyethane (DME) and diethoxyethane (DEE), tetrahydrofuran (THF), dioxolane (DOX) and the like Examples include cyclic ether, γ-butyrolactone (GBL), acetonitrile (AN), sulfolane (SL), and the like. These organic solvents can be used alone or in the form of a mixture of two or more.
　特に、プロピレンカーボネート(ＰＣ)、エチレンカーボネート(ＥＣ)およびγ－ブチロラクトン(ＧＢＬ)からなる群から選択される少なくとも１種の第１の溶媒と、ジエチルカーボネート(ＤＥＣ)、メチルエチルカーボネート(ＭＥＣ)およびジメチルカーボネート(ＤＭＣ)からなる群から選択される少なくとも１種の鎖状カーボネートからなる第２の溶媒とを含む非水溶媒は、４．４～４．５Ｖの高電位での安定性が高い。そのため、このような非水溶媒を用いた場合は、非水電解質二次電池のサイクル寿命性能を向上することが可能となる。特に、エチレンカーボネートと、ジエチルカーボネートとを含む非水溶媒は、４．４～４．５Ｖの高電位での安定性に優れており、非水電解質の酸化分解を抑制することができる。 In particular, at least one first solvent selected from the group consisting of propylene carbonate (PC), ethylene carbonate (EC) and γ-butyrolactone (GBL), diethyl carbonate (DEC), methyl ethyl carbonate (MEC) and A non-aqueous solvent including a second solvent composed of at least one chain carbonate selected from the group consisting of dimethyl carbonate (DMC) has high stability at a high potential of 4.4 to 4.5V. Therefore, when such a nonaqueous solvent is used, the cycle life performance of the nonaqueous electrolyte secondary battery can be improved. In particular, a nonaqueous solvent containing ethylene carbonate and diethyl carbonate is excellent in stability at a high potential of 4.4 to 4.5 V, and can suppress oxidative decomposition of the nonaqueous electrolyte.
　第１の溶媒と第２の溶媒とを含む非水溶媒において、第２の溶媒の配合比は７０体積％以上であることが好ましい。 In the non-aqueous solvent containing the first solvent and the second solvent, the blending ratio of the second solvent is preferably 70% by volume or more.
　非水電解質は、添加剤をさらに含むことができる。添加剤としては、特に限定されないが、例えば、ビニレンカーボネート(vinylene carbonate；ＶＣ)、ビニレンアセテート(vinylene acetate；ＶＡ)、ビニレンブチレート、ビニレンヘキサネート、ビニレンクロトネート、カテコールカーボネート、プロパンスルトン、ジフルオロリン酸リチウム(ＬｉＰＦ２Ｏ２)等が挙げられる。 The non-aqueous electrolyte can further include an additive. Although it does not specifically limit as an additive, For example, vinylene carbonate (vinylene carbonate; VC), vinylene acetate (vinylene acetate; VA), vinylene butyrate, vinylene hexanate, vinylene crotonate, catechol carbonate, propane sultone, difluoro phosphorus Examples include lithium acid (LiPF 2 O 2 ).
　特に、添加剤としてジフルオロリン酸リチウム(ＬｉＰＦ２Ｏ２)を含むものが好ましい。これにより高温耐久性を大幅に向上させることができる。 In particular, an additive containing lithium difluorophosphate (LiPF 2 O 2 ) is preferable. Thereby, high temperature durability can be improved significantly.
　添加剤の濃度は、非水電解質１００質量％に対して、０．１質量％以上３質量％以下の範囲であることが好ましい。添加剤の濃度のより好ましい範囲は、０．５質量％以上２．５質量％以下である。 The concentration of the additive is preferably in the range of 0.1% by mass to 3% by mass with respect to 100% by mass of the nonaqueous electrolyte. A more preferable range of the concentration of the additive is 0.5% by mass or more and 2.5% by mass or less.
　（セパレータ）
　セパレータとしては、例えば、ポリエチレン(polyethylene；ＰＥ)、ポリプロピレン(polypropylene；ＰＰ)、ポリエチレンテレフタレート(polyethylene terephthalate；ＰＥＴ)、セルロース及びポリフッ化ビニリデン(ＰＶｄＦ)のような材料から形成された多孔質フィルム、合成樹脂製不織布等を用いることができる。さらに多孔質フィルムに無機化合物を塗布したセパレータも使用できる。 (Separator)
As the separator, for example, a porous film formed from a material such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), cellulose, and polyvinylidene fluoride (PVdF), synthetic A resin nonwoven fabric or the like can be used. Furthermore, the separator which apply | coated the inorganic compound to the porous film can also be used.
　（外装部材）
　外装部材としては、ラミネートフィルム製の袋状容器又は金属製容器が用いられる。 (Exterior material)
As the exterior member, a laminated film bag-like container or a metal container is used.
　形状としては、扁平型、角型、円筒型、コイン型、ボタン型、シート型、積層型等が挙げられる。無論、携帯用電子機器等に積載される小型電池の他、二輪乃至四輪の自動車等に積載される大型電池でも良い。 Examples of the shape include a flat type, a square type, a cylindrical type, a coin type, a button type, a sheet type, and a laminated type. Of course, in addition to a small battery mounted on a portable electronic device or the like, a large battery mounted on a two-wheel or four-wheel automobile or the like may be used.
　ラミネートフィルムとしては、樹脂フィルム間に金属層を介在した多層フィルムが用いられる。金属層は、軽量化のためにアルミニウム箔もしくはアルミニウム合金箔が好ましい。樹脂フィルムには、例えばポリプロピレン(polypropylene；ＰＰ)、ポリエチレン(polyethylene；ＰＥ)、ナイロン、及びポリエチレンテレフタレート(polyethylene terephthalate；ＰＥＴ)のような高分子材料を用いることができる。ラミネートフィルムは、熱融着によりシールを行って外装部材の形状に成形することができる。ラミネートフィルムは、肉厚が０．２ｍｍ以下であることが好ましい。 As the laminate film, a multilayer film in which a metal layer is interposed between resin films is used. The metal layer is preferably an aluminum foil or an aluminum alloy foil for weight reduction. For the resin film, for example, a polymer material such as polypropylene (PP), polyethylene (PE), nylon, and polyethylene terephthalate (PET) can be used. The laminate film can be formed into the shape of an exterior member by sealing by heat sealing. The laminate film preferably has a thickness of 0.2 mm or less.
　金属製容器は、アルミニウム又はアルミニウム合金から形成されることができる。アルミニウム合金は、マグネシウム、亜鉛及びケイ素のような元素を含むことが好ましい。一方、鉄、銅、ニッケル、クロム等の遷移金属の含有量は１００ｐｐｍ以下にすることが好ましい。これにより、高温環境下での長期信頼性、放熱性を飛躍的に向上させることが可能となる。金属製容器は、肉厚が０．５ｍｍ以下であることが好ましく、肉厚が０．２ｍｍ以下であることがより好ましい。 The metal container can be formed from aluminum or an aluminum alloy. The aluminum alloy preferably contains elements such as magnesium, zinc and silicon. On the other hand, the content of transition metals such as iron, copper, nickel and chromium is preferably 100 ppm or less. Thereby, it becomes possible to dramatically improve long-term reliability and heat dissipation in a high temperature environment. The metal container preferably has a thickness of 0.5 mm or less, and more preferably has a thickness of 0.2 mm or less.
　（負極端子）
　負極端子は、リチウムイオン金属に対する電位が１．０Ｖ以上３．０Ｖ以下の範囲において電気的に安定であり、かつ導電性を有する材料から形成される。負極端子は、アルミニウム、又は、Ｍｇ，Ｔｉ，Ｚｎ，Ｍｎ，Ｆｅ，Ｃｕ，Ｓｉのような元素を含むアルミニウム合金から形成されることが好ましい。負極端子は、負極集電体との接触抵抗を低減するために、負極集電体と同様の材料から形成されることが好ましい。 (Negative terminal)
The negative electrode terminal is formed of a material that is electrically stable and has conductivity in a range where the potential with respect to the lithium ion metal is 1.0 V or more and 3.0 V or less. The negative electrode terminal is preferably formed from aluminum or an aluminum alloy containing an element such as Mg, Ti, Zn, Mn, Fe, Cu, and Si. The negative electrode terminal is preferably formed from the same material as the negative electrode current collector in order to reduce the contact resistance with the negative electrode current collector.
　また、負極集電体において、その上に負極合剤層が形成されていない部分を負極集電タブとすることができる。この負極集電タブに、負極端子を溶接することができる。負極集電体の表面にアンダーコート層が形成されている場合は、負極集電タブの表面にアンダーコート層が形成されていても、そこに負極端子を溶接することができる。または、アンダーコート層が形成されていない部分を負極集電タブとし、負極端子を溶接してもよい。 Further, in the negative electrode current collector, a portion where the negative electrode mixture layer is not formed thereon can be used as a negative electrode current collecting tab. A negative electrode terminal can be welded to the negative electrode current collecting tab. When the undercoat layer is formed on the surface of the negative electrode current collector, the negative electrode terminal can be welded to the undercoat layer even if the undercoat layer is formed on the surface of the negative electrode current collector tab. Alternatively, the portion where the undercoat layer is not formed may be used as a negative electrode current collecting tab, and the negative electrode terminal may be welded.
　（正極端子）
　正極端子は、リチウムイオン金属に対する電位が３．０Ｖ以上４．５Ｖ以下の範囲において電気的に安定であり、且つ導電性を有する材料から形成される。正極端子は、アルミニウム、或いは、Ｍｇ、Ｔｉ、Ｚｎ、Ｍｎ、Ｆｅ、Ｃｕ及びＳｉのような元素を含むアルミニウム合金から形成されることが好ましい。正極端子は、正極集電体との接触抵抗を低減するために、正極集電体と同様の材料から形成されることが好ましい。 (Positive terminal)
The positive electrode terminal is formed of a material that is electrically stable and has electrical conductivity in a range where the potential with respect to the lithium ion metal is 3.0 V or more and 4.5 V or less. The positive electrode terminal is preferably formed from aluminum or an aluminum alloy containing elements such as Mg, Ti, Zn, Mn, Fe, Cu, and Si. The positive electrode terminal is preferably formed of the same material as the positive electrode current collector in order to reduce contact resistance with the positive electrode current collector.
　以上説明した第１の実施形態によれば、非水電解質二次電池を提供することができる。実施形態に係る非水電解質二次電池は、正極と、金属箔からなる負極集電体とリチウムイオンを吸蔵および放出するチタン含有金属酸化物と結着剤とを含んだ負極と、非水電解質と、を含む非水電解質二次電池である。ここで、チタン含有金属酸化物と結着剤とは、上記負極集電体の上に配置されている負極合剤層を構成する。結着剤は、アクリル系樹脂を含む。負極集電体と負極合剤層との剥離強度をα（Ｎ／ｍ）とし、該負極合剤層において表面・界面切削法により測定される切削強度をβ（Ｎ／ｍ）とした場合、これらαおよびβは、α／β＞１．３６×１０－２の関係を満たす。このような構成を有するため、この非水電解質二次電池は、負極集電体と負極合剤層との密着性に優れた負極を有する。そのため、該非水電解質二次電池は、出力性能に優れ、かつ高温耐久性（サイクル性能）に優れている。 According to the first embodiment described above, a nonaqueous electrolyte secondary battery can be provided. A nonaqueous electrolyte secondary battery according to an embodiment includes a positive electrode, a negative electrode current collector made of a metal foil, a negative electrode containing a titanium-containing metal oxide that absorbs and releases lithium ions, and a binder, and a nonaqueous electrolyte And a non-aqueous electrolyte secondary battery. Here, the titanium-containing metal oxide and the binder constitute a negative electrode mixture layer disposed on the negative electrode current collector. The binder includes an acrylic resin. When the peel strength between the negative electrode current collector and the negative electrode mixture layer is α (N / m), and the cutting strength measured by the surface / interface cutting method in the negative electrode mixture layer is β (N / m), These α and β satisfy the relationship of α / β> 1.36 × 10 −2 . Since it has such a configuration, this nonaqueous electrolyte secondary battery has a negative electrode excellent in adhesion between the negative electrode current collector and the negative electrode mixture layer. Therefore, the nonaqueous electrolyte secondary battery is excellent in output performance and excellent in high temperature durability (cycle performance).
　［第２の実施形態］
　次に、第２の実施形態に係る電池パックについて詳細に説明する。 [Second Embodiment]
Next, the battery pack according to the second embodiment will be described in detail.
　第２の実施形態に係る電池パックは、上記の第１の実施形態に係る非水電解質二次電池（即ち、単電池）を少なくとも１つ有する。電池パックに複数の単電池が含まれる場合、各単電池は、電気的に直列、並列、或いは、直列と並列との組み合わせに接続して配置される。 The battery pack according to the second embodiment has at least one non-aqueous electrolyte secondary battery (that is, a single battery) according to the first embodiment. When the battery pack includes a plurality of single cells, the single cells are electrically connected in series, parallel, or a combination of series and parallel.
　このような電池パックを図５および図６を参照して詳細に説明する。図５に示す電池パックにおいては、単電池２１として、図１に示す扁平型非水電解質二次電池を使用している。 Such a battery pack will be described in detail with reference to FIG. 5 and FIG. In the battery pack shown in FIG. 5, the flat type nonaqueous electrolyte secondary battery shown in FIG. 1 is used as the unit cell 21.
　複数の単電池２１は、外部に延出した負極端子６および正極端子７が同じ向きに揃えられるように積層され、粘着テープ２２で締結することによって組電池２３を構成している。これらの単電池２１は、図６に示すように、互いに電気的に直列に接続されている。 The plurality of single cells 21 are laminated so that the negative electrode terminal 6 and the positive electrode terminal 7 extending to the outside are aligned in the same direction, and are fastened with an adhesive tape 22 to constitute an assembled battery 23. These unit cells 21 are electrically connected to each other in series as shown in FIG.
　プリント配線基板２４は、単電池２１の側面のうち、負極端子６および正極端子７が延出する側面と対向して配置されている。プリント配線基板２４には、図６に示すようにサーミスタ２５、保護回路２６および外部機器への通電用端子２７が搭載されている。なお、組電池２３と対向する保護回路基板２４の面には組電池２３の配線と不要な接続を回避するために絶縁板（図示せず）が取り付けられている。 The printed wiring board 24 is disposed to face the side surface of the unit cell 21 where the negative electrode terminal 6 and the positive electrode terminal 7 extend. As shown in FIG. 6, the printed wiring board 24 is mounted with a thermistor 25, a protection circuit 26, and a terminal 27 for energizing external devices. An insulating plate (not shown) is attached to the surface of the protection circuit board 24 facing the assembled battery 23 in order to avoid unnecessary connection with the wiring of the assembled battery 23.
　正極側リード２８は、組電池２３の最下層に位置する正極端子７に接続され、その先端はプリント配線基板２４の正極側コネクタ２９に挿入されて電気的に接続されている。負極側リード３０は、組電池２３の最上層に位置する負極端子６に接続され、その先端はプリント配線基板２４の負極側コネクタ３１に挿入されて電気的に接続されている。これらのコネクタ２９，３１は、プリント配線基板２４に形成された配線３２，３３を通して保護回路２６に接続されている。 The positive electrode side lead 28 is connected to the positive electrode terminal 7 located in the lowermost layer of the assembled battery 23, and the tip thereof is inserted into the positive electrode side connector 29 of the printed wiring board 24 and electrically connected thereto. The negative electrode side lead 30 is connected to the negative electrode terminal 6 located in the uppermost layer of the assembled battery 23, and the tip thereof is inserted into the negative electrode side connector 31 of the printed wiring board 24 and electrically connected thereto. These connectors 29 and 31 are connected to the protection circuit 26 through wirings 32 and 33 formed on the printed wiring board 24.
　サーミスタ２５は、単電池２１の温度を検出し、その検出信号は保護回路２６に送信される。保護回路２６は、所定の条件で保護回路２６と外部機器への通電用端子２７との間のプラス側配線３４ａおよびマイナス側配線３４ｂを遮断できる。所定の条件とは、例えばサーミスタ２５の検出温度が所定温度以上になったときである。また、所定の条件とは単電池２１の過充電、過放電、過電流等を検出したときである。この過充電等の検出は、個々の単電池２１もしくは単電池２１全体について行われる。個々の単電池２１を検出する場合、電池電圧を検出してもよいし、正極電位もしくは負極電位を検出してもよい。後者の場合、個々の単電池２１中に参照極として用いるリチウム電極が挿入される。図５および図６の場合、単電池２１それぞれに電圧検出のための配線３５を接続し、これら配線３５を通して検出信号が保護回路２６に送信される。 The thermistor 25 detects the temperature of the unit cell 21, and the detection signal is transmitted to the protection circuit 26. The protection circuit 26 can cut off the plus side wiring 34a and the minus side wiring 34b between the protection circuit 26 and the energization terminal 27 to the external device under a predetermined condition. The predetermined condition is, for example, when the temperature detected by the thermistor 25 is equal to or higher than a predetermined temperature. The predetermined condition is when the overcharge, overdischarge, overcurrent, etc. of the cell 21 are detected. This detection of overcharge or the like is performed for each single cell 21 or the entire single cell 21. When detecting each single cell 21, the battery voltage may be detected, or the positive electrode potential or the negative electrode potential may be detected. In the latter case, a lithium electrode used as a reference electrode is inserted into each unit cell 21. In the case of FIG. 5 and FIG. 6, a wiring 35 for voltage detection is connected to each single cell 21, and a detection signal is transmitted to the protection circuit 26 through these wirings 35.
　組電池２３の三側面には、ゴムもしくは樹脂からなる保護シート３６がそれぞれ配置されている。具体的には、保護シート３６は、組電池２３の側面のうち正極端子７および負極端子６が突出する側面以外の三側面に配置されている。 Protective sheets 36 made of rubber or resin are respectively disposed on the three side surfaces of the assembled battery 23. Specifically, the protective sheet 36 is disposed on three side surfaces of the assembled battery 23 other than the side surfaces from which the positive electrode terminal 7 and the negative electrode terminal 6 protrude.
　組電池２３は、各保護シート３６およびプリント配線基板２４と共に収納容器３７内に収納される。すなわち、収納容器３７の長辺方向に沿った両方の内側面と短辺方向に沿った一方の内側面のそれぞれに保護シート３６が配置されている。短辺方向に沿って配置されている保護シート３６の反対側の内側面にプリント配線基板２４が配置される。組電池２３は、保護シート３６およびプリント配線基板２４で囲まれた空間内に位置する。蓋３８は、収納容器３７の上面に取り付けられている。 The assembled battery 23 is stored in a storage container 37 together with each protective sheet 36 and the printed wiring board 24. That is, the protective sheet 36 is disposed on each of both inner side surfaces along the long side direction of the storage container 37 and one inner side surface along the short side direction. The printed wiring board 24 is disposed on the inner surface on the opposite side of the protective sheet 36 disposed along the short side direction. The assembled battery 23 is located in a space surrounded by the protective sheet 36 and the printed wiring board 24. The lid 38 is attached to the upper surface of the storage container 37.
　なお、組電池２３の固定には粘着テープ２２に代えて、熱収縮テープを用いてもよい。この場合、組電池の両側面に保護シートを配置し、熱収縮テープを周回させた後、熱収縮テープを熱収縮させて組電池を結束させる。 In addition, instead of the adhesive tape 22, a heat shrink tape may be used for fixing the assembled battery 23. In this case, protective sheets are arranged on both side surfaces of the assembled battery, the heat shrinkable tape is circulated, and then the heat shrinkable tape is heat shrunk to bind the assembled battery.
　図５、図６では単電池２１を直列接続した形態を示したが、電池容量を増大させるためには並列に接続してもよい。組み上がった電池パックを直列、並列に接続することもできる。 5 and 6 show a configuration in which the cells 21 are connected in series, but in order to increase the battery capacity, they may be connected in parallel. The assembled battery packs can be connected in series or in parallel.
　なお、電池パックの態様は用途により適宜変更される。実施形態に係る電池パックの用途としては、大電流を取り出したときに優れたサイクル性能を示すことが要求されるものが好ましい。具体的には、デジタルカメラの電源用や、二輪乃至四輪のハイブリッド電気自動車、二輪乃至四輪の電気自動車、アシスト自転車等の車載用が挙げられる。特に、高温耐久性の優れた非水電解質二次電池を用いた電池パックは、車載用に好適に用いられる。 In addition, the aspect of a battery pack is changed suitably according to a use. As a use of the battery pack according to the embodiment, one that is required to exhibit excellent cycle performance when a large current is taken out is preferable. Specific examples include a power source for a digital camera, a vehicle for a two- to four-wheel hybrid electric vehicle, a two- to four-wheel electric vehicle, an assist bicycle, and the like. In particular, a battery pack using a nonaqueous electrolyte secondary battery excellent in high temperature durability is suitably used for in-vehicle use.
　さらに、自動車のエンジンルームは、内部温度が高くなる懸念がある。第２の実施形態に係る電池パックは、優れた高温耐久性を有する非水電解質二次電池を具備しているため、自動車のエンジンルームに配置した場合でも、好適に用いることができる。 Furthermore, there is a concern that the internal temperature of the engine room of a car will increase. Since the battery pack according to the second embodiment includes a non-aqueous electrolyte secondary battery having excellent high-temperature durability, it can be suitably used even when placed in the engine room of an automobile.
　以上説明した第２の実施形態によれば、電池パックを提供することができる。実施形態に係る電池パックは、上記の第１の実施形態に係る非水電解質二次電池を少なくとも１つ具備する。このような電池パックは、高い出力と高温での高耐久性とを示すことができる。 According to the second embodiment described above, a battery pack can be provided. The battery pack according to the embodiment includes at least one nonaqueous electrolyte secondary battery according to the first embodiment. Such a battery pack can exhibit high output and high durability at high temperatures.
　[実施例]
　以下に実施例を説明するが、本発明の主旨を超えない限り、本発明は以下に掲載される実施例に限定されるものでない。 [Example]
Examples will be described below, but the present invention is not limited to the examples described below unless the gist of the present invention is exceeded.
　＜実施例１～１３＞
　（実施例１）
　以下の手順により、図１～図２に示す非水電解質二次電池と同様の非水電解質二次電池を作製した。 <Examples 1 to 13>
(Example 1)
A non-aqueous electrolyte secondary battery similar to the non-aqueous electrolyte secondary battery shown in FIGS. 1 and 2 was produced by the following procedure.
　＜負極の作製＞
　負極活物質として、リチウム金属の電極電位に対するリチウム吸蔵放出電位が２Ｖから１．３Ｖ（ｖｓ．Ｌｉ／Ｌｉ+）のスピネル構造で、一次粒子の平均粒径が０．８μｍのチタン酸リチウム（Ｌｉ４Ｔｉ５Ｏ１２）粒子を用意した。 <Production of negative electrode>
As a negative electrode active material, lithium titanate (Li) having a spinel structure with a lithium occlusion / release potential of 2 V to 1.3 V (vs. Li / Li + ) with respect to the electrode potential of lithium metal and an average primary particle size of 0.8 μm. 4 Ti 5 O 12) were prepared particles.
　このチタン酸リチウムを９０重量％、導電剤としてのアセチレンブラックを５重量％、結着剤としてのポリアクリロニトリルを５重量％配合し、Ｎ－メチルピロリドン(ＮＭＰ)を固形分比が７０重量％になるように添加した。これをプラネタリ―ミキサ（プライミクス株式会社製　ハイビスディスパ―ミックス　３Ｄ－０５）で混練し、ＮＭＰを加えながら固形分比を徐々に低下させてスラリーを調整した。 90% by weight of this lithium titanate, 5% by weight of acetylene black as a conductive agent, 5% by weight of polyacrylonitrile as a binder, and a solid content ratio of 70% by weight of N-methylpyrrolidone (NMP) It added so that it might become. This was kneaded with a planetary mixer (Hibis Dispersix 3D-05 manufactured by PRIMIX Corporation), and the slurry was adjusted by gradually reducing the solid content ratio while adding NMP.
　このスラリーを、連続式ビーズミル（アイメックス株式会社製　ＲＭＨ－０３）を用い、回転数１５００ｒｐｍ、流量３０ｃｃ／分の条件で湿式粉砕・分散処理し、スラリーを調整した。 The slurry was wet pulverized and dispersed using a continuous bead mill (RMH-03, manufactured by IMEX Co., Ltd.) under the conditions of a rotational speed of 1500 rpm and a flow rate of 30 cc / min to prepare a slurry.
　続いて、このスラリーを、厚さが１５μｍで、その表面に厚さ１μｍのアンダーコート層（炭素樹脂層）が両面に形成されたアルミニウム箔である負極集電体の両面に、スロットダイ式塗工装置（株式会社廉井精機製）により塗工速度０．７５ｍ／分の速度で塗布し、乾燥温度１４０℃で乾燥させた。この際、負極集電体に、表面にスラリーが塗布されていない部分を残した。 Subsequently, the slurry was applied to both sides of a negative electrode current collector, which is an aluminum foil having a thickness of 15 μm and an undercoat layer (carbon resin layer) having a thickness of 1 μm formed on both surfaces. It was applied at a coating speed of 0.75 m / min using a construction apparatus (manufactured by Yurai Seiki Co., Ltd.) and dried at a drying temperature of 140 ° C. At this time, a portion of the negative electrode current collector where the slurry was not applied was left on the surface.
　更に、得られた塗布電極を、ロールプレス装置（大野ロール製）によりプレス温度２５℃でプレスを行い、片面あたりの厚さが２０μｍ、電極密度が２．０ｇ／ｃｍ３の負極合剤層を負極集電体上に形成した。次に、負極集電体において、負極合剤層が表面に形成されていない部分を帯状に打ち抜き、負極集電タブを形成した。このようにして負極を作製した。 Furthermore, the obtained coated electrode was pressed at a pressing temperature of 25 ° C. by a roll press apparatus (manufactured by Ohno Roll), and a negative electrode mixture layer having a thickness of 20 μm per side and an electrode density of 2.0 g / cm 3 was obtained. It formed on the negative electrode collector. Next, in the negative electrode current collector, a portion where the negative electrode mixture layer was not formed on the surface was punched into a band shape to form a negative electrode current collecting tab. In this way, a negative electrode was produced.
　＜正極の作製＞
　正極活物質として、中心粒子径７．５μｍのニッケルコバルトマンガン酸リチウム（ＬｉＮｉ０．３４Ｃｏ０．３３Ｍｎ０．３３Ｏ２）粒子を用意した。このニッケルコバルトマンガン酸リチウムを９０重量％、導電剤としてのアセチレンブラック及び黒鉛粉末を、それぞれ３重量％と２重量％、結着剤としてのポリアクリル酸（平均分子量４５万）を５重量％配合してＮ－メチルピロリドン（ＮＭＰ）溶媒に分散してスラリーを調整した。アルミニウム箔である厚さ１５μｍの正極集電体の両面にスラリーを塗布した。この際、正極集電体に、表面にスラリーが塗布されていない部分を残した。 <Preparation of positive electrode>
As the positive electrode active material, nickel cobalt lithium manganate (LiNi 0.34 Co 0.33 Mn 0.33 O 2 ) particles having a center particle diameter of 7.5 μm were prepared. 90% by weight of this nickel cobalt lithium manganate, 3% and 2% by weight of acetylene black and graphite powder as a conductive agent, and 5% by weight of polyacrylic acid (average molecular weight 450,000) as a binder, respectively. Then, the slurry was prepared by dispersing in N-methylpyrrolidone (NMP) solvent. The slurry was applied to both surfaces of a positive electrode current collector having a thickness of 15 μm, which was an aluminum foil. At this time, a portion where the slurry was not applied on the surface was left on the positive electrode current collector.
　塗布したスラリーを乾燥させて、プレスし、電極密度が３．２ｇ／ｃｍ３の正極合剤層を正極集電体上に形成した。正極の重量は負極重量の１．１倍となるように調整した。次に、正極集電体において、正極合剤層が表面に形成されていない部分を帯状に打ち抜き、正極集電タブを形成した。こうして正極を作製した。 The applied slurry was dried and pressed to form a positive electrode mixture layer having an electrode density of 3.2 g / cm 3 on the positive electrode current collector. The weight of the positive electrode was adjusted to be 1.1 times the weight of the negative electrode. Next, in the positive electrode current collector, a portion where the positive electrode mixture layer was not formed on the surface was punched into a band shape to form a positive electrode current collector tab. In this way, a positive electrode was produced.
　＜電極群の作製＞
　正極、厚さ２０μｍの不織布セパレータ、負極およびセパレータをこの順序で積層した後、渦巻き状に捲回した。これを９０℃で加熱プレスすることにより、幅が３０ｍｍ、厚さ３．０ｍｍの偏平状電極群を作製した。得られた電極群をラミネートフィルムからなるパックに収納し、８０℃で２４時間真空乾燥を施した。ラミネートフィルムとしては、厚さ４０μｍのアルミニウム箔の両面にポリプロピレン層を形成して構成され、全体の厚さが０．１ｍｍであるものを用いた。 <Production of electrode group>
A positive electrode, a nonwoven fabric separator having a thickness of 20 μm, a negative electrode and a separator were laminated in this order, and then wound in a spiral shape. This was heated and pressed at 90 ° C. to produce a flat electrode group having a width of 30 mm and a thickness of 3.0 mm. The obtained electrode group was housed in a pack made of a laminate film and vacuum dried at 80 ° C. for 24 hours. As the laminate film, one having a polypropylene layer formed on both sides of an aluminum foil having a thickness of 40 μm and having an overall thickness of 0.1 mm was used.
　＜液状非水電解質の調製＞
　プロピレンカーボネート(ＰＣ)およびジエチルカーボネート(ＤＥＣ)を１：１の体積比率で混合して混合溶媒とした。この混合溶媒に電解質であるＬｉＰＦ６を１．５ｍｏｌ／Ｌ溶解させ、液状非水電解質を調製した。 <Preparation of liquid nonaqueous electrolyte>
Propylene carbonate (PC) and diethyl carbonate (DEC) were mixed at a volume ratio of 1: 1 to obtain a mixed solvent. LiPF 6 which is an electrolyte was dissolved in this mixed solvent at 1.5 mol / L to prepare a liquid non-aqueous electrolyte.
　＜非水電解質二次電池の作製＞
　電極群を収納したラミネートフィルムのパック内に液状非水電解質を注入した。その後、パックをヒートシールにより完全密閉し、前述した図１に示す構造を有し、幅３５ｍｍ、厚さ３．５ｍｍ、高さが６５ｍｍの非水電解質二次電池（設計容量１Ａｈ）を作製した。これを実施例１の二次電池とした。 <Preparation of nonaqueous electrolyte secondary battery>
A liquid non-aqueous electrolyte was poured into a laminate film pack containing the electrode group. Thereafter, the pack was completely sealed by heat sealing, and a non-aqueous electrolyte secondary battery (design capacity 1 Ah) having the structure shown in FIG. 1 and having a width of 35 mm, a thickness of 3.5 mm, and a height of 65 mm was produced. . This was designated as the secondary battery of Example 1.
　上記実施例１および下記実施例２～１３において、負極の作製において用いた負極活物質および結着剤種、並びに正極の作製において用いた正極活物質を表１にまとめる。表２には、負極集電体におけるアンダーコート層の有無およびその厚さをまとめる。また、実施例１～１３における負極作製の条件（スラリーの塗工速度、スラリーの乾燥温度、プレス温度）を表３にまとめる。表３は、後述するように求められた、実施例１～１３についての負極集電体と負極合剤層との剥離強度α、負極合剤層における切削強度β、およびこれらの比（α／β）の値をさらに示す。 Table 1 summarizes the negative electrode active material and binder used in the production of the negative electrode and the positive electrode active material used in the production of the positive electrode in Example 1 and Examples 2 to 13 below. Table 2 summarizes the presence and thickness of the undercoat layer in the negative electrode current collector. Table 3 summarizes the conditions for producing the negative electrodes (slurry coating speed, slurry drying temperature, press temperature) in Examples 1 to 13. Table 3 shows the peel strength α between the negative electrode current collector and the negative electrode mixture layer, the cutting strength β in the negative electrode mixture layer, and the ratio (α / The value of β) is further shown.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　（実施例２）
　実施例１における負極の作製と同様にしてスラリーを調整した。また、実施例１の負極に用いたと同様の負極集電体を準備した。このスラリーを負極集電体の両面に塗布する際に、塗工速度を１．０ｍ／分の速度としたこと以外は、実施例１と同様にして負極を作製した。 (Example 2)
A slurry was prepared in the same manner as in the preparation of the negative electrode in Example 1. Also, a negative electrode current collector similar to that used for the negative electrode of Example 1 was prepared. A negative electrode was produced in the same manner as in Example 1, except that the coating speed was 1.0 m / min when this slurry was applied to both surfaces of the negative electrode current collector.
　この負極を用いたことを除き、実施例１と同様にして設計容量１Ａｈの非水電解質二次電池を作製した。これを実施例２の二次電池とした。 A nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 1 except that this negative electrode was used. This was designated as the secondary battery of Example 2.
　（実施例３）
　実施例１における負極の作製と同様にしてスラリーを調整した。また、実施例１の負極に用いたと同様の負極集電体を準備した。このスラリーを負極集電体の両面に塗布する際に、塗工速度を１．５ｍ／分の速度としたこと以外は、実施例１と同様にして負極を作製した。 (Example 3)
A slurry was prepared in the same manner as in the preparation of the negative electrode in Example 1. Also, a negative electrode current collector similar to that used for the negative electrode of Example 1 was prepared. A negative electrode was produced in the same manner as in Example 1 except that when the slurry was applied to both surfaces of the negative electrode current collector, the coating speed was 1.5 m / min.
　この負極を用いたことを除き、実施例１と同様にして設計容量１Ａｈの非水電解質二次電池を作製した。これを実施例３の二次電池とした。 A nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 1 except that this negative electrode was used. This was designated as the secondary battery of Example 3.
　（実施例４）
　負極活物質として、実施例１で使用したものと同じチタン酸リチウム（Ｌｉ４Ｔｉ５Ｏ１２）粒子を用意した。 (Example 4)
As the negative electrode active material, the same lithium titanate (Li 4 Ti 5 O 12 ) particles as those used in Example 1 were prepared.
　このチタン酸リチウムを９０重量％、導電剤としてのアセチレンブラックを５重量％、結着剤としてのポリアクリロニトリル及びポリアクリル酸（平均分子量４５万）を、それぞれ３重量％と２重量％配合し、Ｎ－メチルピロリドン(ＮＭＰ)溶媒に分散してスラリーを調整した。 90% by weight of this lithium titanate, 5% by weight of acetylene black as a conductive agent, and 3% by weight and 2% by weight of polyacrylonitrile and polyacrylic acid (average molecular weight 450,000) as binders, A slurry was prepared by dispersing in N-methylpyrrolidone (NMP) solvent.
　このスラリーを用いて、これを負極集電体の両面に塗布する際の塗工速度を１．０ｍ／分の速度としたこと以外は、実施例１と同様にして負極を作製した。 Using this slurry, a negative electrode was produced in the same manner as in Example 1 except that the coating speed when applying this to both surfaces of the negative electrode current collector was 1.0 m / min.
　この負極を用いたことを除き、実施例２と同様にして設計容量１Ａｈの非水電解質二次電池を作製した。これを実施例４の二次電池とした。 A nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 2 except that this negative electrode was used. This was designated as the secondary battery of Example 4.
　（実施例５）
　負極活物質として、実施例１で使用したものと同じチタン酸リチウム（Ｌｉ４Ｔｉ５Ｏ１２）粒子を用意した。このチタン酸リチウムを９０重量％、導電剤としてのアセチレンブラックを７重量％、結着剤としてのポリアクリル酸（平均分子量４５万）を３重量％配合し、Ｎ－メチルピロリドン(ＮＭＰ)溶媒に分散してスラリーを調整した。 (Example 5)
As the negative electrode active material, the same lithium titanate (Li 4 Ti 5 O 12 ) particles as those used in Example 1 were prepared. 90% by weight of this lithium titanate, 7% by weight of acetylene black as a conductive agent, and 3% by weight of polyacrylic acid (average molecular weight 450,000) as a binder were blended into an N-methylpyrrolidone (NMP) solvent. The slurry was prepared by dispersing.
　このスラリーを、厚さ１５μｍで、その表面に厚さ０．３μｍのアンダーコート層（炭素樹脂層）が両面に形成されたアルミニウム箔である負極集電体の両面に塗布した。この際、負極集電体に、表面にスラリーが塗布されていない部分を残した。 This slurry was applied to both surfaces of a negative electrode current collector, which was an aluminum foil having a thickness of 15 μm and an undercoat layer (carbon resin layer) having a thickness of 0.3 μm formed on both surfaces. At this time, a portion of the negative electrode current collector where the slurry was not applied was left on the surface.
　塗布したスラリーを乾燥させて、プレスし、片面あたりの厚さが２０μｍ、電極密度２．０ｇ／ｃｍ３の負極合剤層を負極集電体上に形成した。この時の塗工速度、乾燥温度、およびプレス温度は、表３に示す条件にて行った。次に、負極集電体において負極層が表面に形成されていない部分を帯状に打ち抜き、負極集電タブを形成した。このようにして負極を作製した。 The applied slurry was dried and pressed to form a negative electrode mixture layer having a thickness of 20 μm on one side and an electrode density of 2.0 g / cm 3 on the negative electrode current collector. The coating speed, drying temperature, and press temperature at this time were performed under the conditions shown in Table 3. Next, a portion of the negative electrode current collector where the negative electrode layer was not formed on the surface was punched into a band shape to form a negative electrode current collector tab. In this way, a negative electrode was produced.
　この負極を用いたことを除き、実施例１と同様にして設計容量１Ａｈの非水電解質二次電池を作製した。これを実施例５の二次電池とした。 A nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 1 except that this negative electrode was used. This was designated as the secondary battery of Example 5.
　（実施例６）
　負極活物質として、実施例１で使用したものと同じチタン酸リチウム（Ｌｉ４Ｔｉ５Ｏ１２）粒子を用意した。このチタン酸リチウムを９０重量％、導電剤としてのアセチレンブラックを４．５重量％、結着剤としてのポリアクリル酸（平均分子量４５万）を５．５重量％配合し、Ｎ－メチルピロリドン(ＮＭＰ)溶媒に分散してスラリーを調整した。 (Example 6)
As the negative electrode active material, the same lithium titanate (Li 4 Ti 5 O 12 ) particles as those used in Example 1 were prepared. 90% by weight of this lithium titanate, 4.5% by weight of acetylene black as a conductive agent, and 5.5% by weight of polyacrylic acid (average molecular weight 450,000) as a binder were blended, and N-methylpyrrolidone ( The slurry was prepared by dispersing in NMP) solvent.
　このスラリーを、厚さ１５μｍで、その表面に厚さ２μｍのアンダーコート層（炭素樹脂層）が両面に形成されたアルミニウム箔である負極集電体の両面に塗布した。この際、負極集電体に、表面にスラリーが塗布されていない部分を残した。 The slurry was applied to both surfaces of a negative electrode current collector, which is an aluminum foil having a thickness of 15 μm and an undercoat layer (carbon resin layer) having a thickness of 2 μm formed on both surfaces. At this time, a portion of the negative electrode current collector where the slurry was not applied was left on the surface.
　塗布したスラリーを乾燥させて、プレスし、片面あたりの厚さが２０μｍ、電極密度２．０ｇ／ｃｍ３の負極合剤層を負極集電体上に形成した。この時の塗工速度、乾燥温度、およびプレス温度は、表３に示す条件にて行った。次に、負極集電体において負極合剤層が表面に形成されていない部分を帯状に打ち抜き、負極集電タブを形成した。このようにして負極を作製した。 The applied slurry was dried and pressed to form a negative electrode mixture layer having a thickness of 20 μm on one side and an electrode density of 2.0 g / cm 3 on the negative electrode current collector. The coating speed, drying temperature, and press temperature at this time were performed under the conditions shown in Table 3. Next, a portion of the negative electrode current collector where the negative electrode mixture layer was not formed on the surface was punched into a band shape to form a negative electrode current collector tab. In this way, a negative electrode was produced.
　この負極を用いたことを除き、実施例１と同様にして設計容量１Ａｈの非水電解質二次電池を作製した。これを実施例６の二次電池とした。 A nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 1 except that this negative electrode was used. This was designated as the secondary battery of Example 6.
　（実施例７）
　実施例１における負極の作製と同様にしてスラリーを調整した。このスラリーを、厚さ１５μｍで、その表面に厚さ０．３μｍのアンダーコート層（炭素樹脂層）が両面に形成されたアルミニウム箔である負極集電体の両面に塗布した。この際、負極集電体に、表面にスラリーが塗布されていない部分を残した。 (Example 7)
A slurry was prepared in the same manner as in the preparation of the negative electrode in Example 1. This slurry was applied to both surfaces of a negative electrode current collector which was an aluminum foil having a thickness of 15 μm and an undercoat layer (carbon resin layer) having a thickness of 0.3 μm formed on both surfaces. At this time, a portion of the negative electrode current collector where the slurry was not applied was left on the surface.
　塗布したスラリーを乾燥させて、プレスし、片面あたりの厚さが２０μｍ、電極密度２．０ｇ／ｃｍ３の負極合剤層を負極集電体上に形成した。この時の塗工速度、乾燥温度、およびプレス温度は、表３に示す条件にて行った。次に、負極集電体において負極合剤層が表面に形成されていない部分を帯状に打ち抜き、負極集電タブを形成した。このようにして負極を作製した。 The applied slurry was dried and pressed to form a negative electrode mixture layer having a thickness of 20 μm on one side and an electrode density of 2.0 g / cm 3 on the negative electrode current collector. The coating speed, drying temperature, and press temperature at this time were performed under the conditions shown in Table 3. Next, a portion of the negative electrode current collector where the negative electrode mixture layer was not formed on the surface was punched into a band shape to form a negative electrode current collector tab. In this way, a negative electrode was produced.
　この負極を用いたことを除き、実施例１と同様にして設計容量１Ａｈの非水電解質二次電池を作製した。これを実施例７の二次電池とした。 A nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 1 except that this negative electrode was used. This was designated as the secondary battery of Example 7.
　（実施例８）
　負極活物質として、実施例１で使用したものと同じチタン酸リチウム（Ｌｉ４Ｔｉ５Ｏ１２）粒子を用意した。このチタン酸リチウムを９０重量％、導電剤としてのアセチレンブラックを５重量％、結着剤としてのポリアクリロニトリル及びポリアクリル酸（平均分子量３００万）を、それぞれ３重量％と２重量％配合し、Ｎ－メチルピロリドン(ＮＭＰ)溶媒に分散してスラリーを調整した。 (Example 8)
As the negative electrode active material, the same lithium titanate (Li 4 Ti 5 O 12 ) particles as those used in Example 1 were prepared. 90% by weight of this lithium titanate, 5% by weight of acetylene black as a conductive agent, and polyacrylonitrile and polyacrylic acid (average molecular weight of 3 million) as binders were blended by 3% by weight and 2% by weight, respectively. A slurry was prepared by dispersing in N-methylpyrrolidone (NMP) solvent.
　このスラリーを、厚さ１５μｍで、その表面に厚さ０．３μｍのアンダーコート層（炭素樹脂層）が両面に形成されたアルミニウム箔である負極集電体の両面に塗布した。この際、負極集電体に、表面にスラリーが塗布されていない部分を残した。 This slurry was applied to both surfaces of a negative electrode current collector, which was an aluminum foil having a thickness of 15 μm and an undercoat layer (carbon resin layer) having a thickness of 0.3 μm formed on both surfaces. At this time, a portion of the negative electrode current collector where the slurry was not applied was left on the surface.
　塗布したスラリーを乾燥させて、プレスし、片面あたりの厚さが２０μｍ、電極密度２．０ｇ／ｃｍ３の負極合剤層を負極集電体上に形成した。この時の塗工速度、乾燥温度、およびプレス温度は、表３に示す条件にて行った。次に、負極集電体において負極合剤層が表面に形成されていない部分を帯状に打ち抜き、負極集電タブを形成した。このようにして負極を作製した。 The applied slurry was dried and pressed to form a negative electrode mixture layer having a thickness of 20 μm on one side and an electrode density of 2.0 g / cm 3 on the negative electrode current collector. The coating speed, drying temperature, and press temperature at this time were performed under the conditions shown in Table 3. Next, a portion of the negative electrode current collector where the negative electrode mixture layer was not formed on the surface was punched into a band shape to form a negative electrode current collector tab. In this way, a negative electrode was produced.
　この負極を用いたことを除き、実施例１と同様にして設計容量１Ａｈの非水電解質二次電池を作製した。これを実施例８の二次電池とした。 A nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 1 except that this negative electrode was used. This was the secondary battery of Example 8.
　（実施例９）
　負極活物質として、実施例１で使用したものと同じチタン酸リチウム（Ｌｉ４Ｔｉ５Ｏ１２）粒子を用意した。このチタン酸リチウムを９０重量％、導電剤としてのアセチレンブラックを５重量％、結着剤としてのポリアクリル酸（平均分子量３００万）を５重量％配合し、Ｎ－メチルピロリドン(ＮＭＰ)溶媒に分散してスラリーを調整した。 Example 9
As the negative electrode active material, the same lithium titanate (Li 4 Ti 5 O 12 ) particles as those used in Example 1 were prepared. 90% by weight of this lithium titanate, 5% by weight of acetylene black as a conductive agent, and 5% by weight of polyacrylic acid (average molecular weight of 3 million) as a binder were blended into an N-methylpyrrolidone (NMP) solvent. The slurry was prepared by dispersing.
　このスラリーを、厚さ１５μｍで、その表面に厚さ２μｍのアンダーコート層（炭素樹脂層）が両面に形成されたアルミニウム箔である負極集電体の両面に塗布した。この際、負極集電体に、表面にスラリーが塗布されていない部分を残した。 The slurry was applied to both surfaces of a negative electrode current collector, which is an aluminum foil having a thickness of 15 μm and an undercoat layer (carbon resin layer) having a thickness of 2 μm formed on both surfaces. At this time, a portion of the negative electrode current collector where the slurry was not applied was left on the surface.
　塗布したスラリーを乾燥させて、プレスし、片面あたりの厚さが２０μｍ、電極密度２．０ｇ／ｃｍ３の負極合剤層を負極集電体上に形成した。この時の塗工速度、乾燥温度、およびプレス温度は、表３に示す条件にて行った。次に、負極集電体において負極合剤層が表面に形成されていない部分を帯状に打ち抜き、負極集電タブを形成した。このようにして負極を作製した。 The applied slurry was dried and pressed to form a negative electrode mixture layer having a thickness of 20 μm on one side and an electrode density of 2.0 g / cm 3 on the negative electrode current collector. The coating speed, drying temperature, and press temperature at this time were performed under the conditions shown in Table 3. Next, a portion of the negative electrode current collector where the negative electrode mixture layer was not formed on the surface was punched into a band shape to form a negative electrode current collector tab. In this way, a negative electrode was produced.
　この負極を用いたことを除き、実施例１と同様にして設計容量１Ａｈの非水電解質二次電池を作製した。これを実施例９の二次電池とした。 A nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 1 except that this negative electrode was used. This was the secondary battery of Example 9.
　（実施例１０）
　負極活物質として、一次粒子の平均粒径が２μｍの単斜晶型チタン複合酸化物(ＴｉＯ２)を用意した。このチタン複合酸化物を９０重量％、導電剤としてのアセチレンブラックを６重量％、結着剤としてのポリアクリロニトリル及びポリアクリル酸（平均分子量４５万）を、それぞれ３重量％と１重量％配合し、Ｎ－メチルピロリドン(ＮＭＰ)溶媒に分散してスラリーを調整した。 (Example 10)
As the negative electrode active material, a monoclinic titanium composite oxide (TiO 2 ) having an average primary particle diameter of 2 μm was prepared. 90% by weight of this titanium composite oxide, 6% by weight of acetylene black as a conductive agent, and 3% by weight and 1% by weight of polyacrylonitrile and polyacrylic acid (average molecular weight 450,000) as binders, respectively. The slurry was prepared by dispersing in N-methylpyrrolidone (NMP) solvent.
　このスラリーを、厚さ１５μｍで、その表面に厚さ０．３μｍのアンダーコート層（炭素樹脂層）が両面に形成されたアルミニウム箔である負極集電体の両面に塗布した。この際、負極集電体に、表面にスラリーが塗布されていない部分を残した。 This slurry was applied to both surfaces of a negative electrode current collector, which was an aluminum foil having a thickness of 15 μm and an undercoat layer (carbon resin layer) having a thickness of 0.3 μm formed on both surfaces. At this time, a portion of the negative electrode current collector where the slurry was not applied was left on the surface.
　塗布したスラリーを乾燥させて、プレスし、片面あたりの厚さが１９μｍ、電極密度２．０ｇ／ｃｍ３の負極合剤層を負極集電体上に形成した。この時の塗工速度、乾燥温度、およびプレス温度は、表３に示す条件にて行った。次に、負極集電体において負極合剤層が表面に形成されていない部分を帯状に打ち抜き、負極集電タブを形成した。このようにして負極を作製した。 The applied slurry was dried and pressed to form a negative electrode mixture layer having a thickness of 19 μm on one side and an electrode density of 2.0 g / cm 3 on the negative electrode current collector. The coating speed, drying temperature, and press temperature at this time were performed under the conditions shown in Table 3. Next, a portion of the negative electrode current collector where the negative electrode mixture layer was not formed on the surface was punched into a band shape to form a negative electrode current collector tab. In this way, a negative electrode was produced.
　この負極を用いたことを除き、実施例１と同様にして設計容量１Ａｈの非水電解質二次電池を作製した。これを実施例１０の二次電池とした。 A nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 1 except that this negative electrode was used. This was the secondary battery of Example 10.
　（実施例１１）
　負極活物質として、一次粒子の平均粒径が１μｍのニオブ含有チタン複合酸化物（ＴｉＮｂ２Ｏ７）を用意した。このニオブ含有チタン複合酸化物を９０重量％、導電剤としてのアセチレンブラックを６重量％、結着剤としてのポリアクリロニトリル及びポリアクリル酸（平均分子量４５万）を、それぞれ３重量％と１重量％配合し、Ｎ－メチルピロリドン(ＮＭＰ)溶媒に分散してスラリーを調整した。 (Example 11)
As the negative electrode active material, a niobium-containing titanium composite oxide (TiNb 2 O 7 ) having an average primary particle size of 1 μm was prepared. 90% by weight of this niobium-containing titanium composite oxide, 6% by weight of acetylene black as a conductive agent, and 3% by weight and 1% by weight of polyacrylonitrile and polyacrylic acid (average molecular weight 450,000) as binders, respectively. A slurry was prepared by mixing and dispersing in an N-methylpyrrolidone (NMP) solvent.
　このスラリーを、厚さ１５μｍで、その表面に厚さ０．３μｍのアンダーコート層（炭素樹脂層）が両面に形成されたアルミニウム箔である負極集電体の両面に塗布した。この際、負極集電体に、表面にスラリーが塗布されていない部分を残した。 This slurry was applied to both surfaces of a negative electrode current collector, which was an aluminum foil having a thickness of 15 μm and an undercoat layer (carbon resin layer) having a thickness of 0.3 μm formed on both surfaces. At this time, a portion of the negative electrode current collector where the slurry was not applied was left on the surface.
　塗布したスラリーを乾燥させて、プレスし、片面あたりの厚さが１５μｍ、電極密度２．４ｇ／ｃｍ３の負極合剤層を負極集電体上に形成した。この時の塗工速度、乾燥温度、およびプレス温度は、表３に示す条件にて行った。次に、負極集電体において負極合剤層が表面に形成されていない部分を帯状に打ち抜き、負極集電タブを形成した。このようにして負極を作製した。 The applied slurry was dried and pressed to form a negative electrode mixture layer having a thickness of 15 μm per side and an electrode density of 2.4 g / cm 3 on the negative electrode current collector. The coating speed, drying temperature, and press temperature at this time were performed under the conditions shown in Table 3. Next, a portion of the negative electrode current collector where the negative electrode mixture layer was not formed on the surface was punched into a band shape to form a negative electrode current collector tab. In this way, a negative electrode was produced.
　この負極を用いたことを除き、実施例１０と同様にして設計容量１Ａｈの非水電解質二次電池を作製した。これを実施例１１の二次電池とした。 A nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 10 except that this negative electrode was used. This was the secondary battery of Example 11.
　（実施例１２）
　負極活物質として、一次粒子の平均粒径が１μｍのナトリウム含有チタン複合酸化物（Ｌｉ２Ｎａ２Ｔｉ６Ｏ１４）を用意した。このナトリウム含有チタン複合酸化物を９０重量％、導電剤としてのアセチレンブラックを６重量％、結着剤としてのポリアクリロニトリル及びポリアクリル酸（平均分子量４５万）を、それぞれ３重量％と１重量％配合し、Ｎ－メチルピロリドン(ＮＭＰ)溶媒に分散してスラリーを調整した。 (Example 12)
As a negative electrode active material, a sodium-containing titanium composite oxide (Li 2 Na 2 Ti 6 O 14 ) having an average primary particle size of 1 μm was prepared. 90% by weight of this sodium-containing titanium composite oxide, 6% by weight of acetylene black as a conductive agent, and 3% by weight and 1% by weight of polyacrylonitrile and polyacrylic acid (average molecular weight 450,000) as binders, respectively. A slurry was prepared by mixing and dispersing in an N-methylpyrrolidone (NMP) solvent.
　このスラリーを、厚さ１５μｍで、その表面に厚さ０．３μｍのアンダーコート層（炭素樹脂層）が両面に形成されたアルミニウム箔である負極集電体の両面に塗布した。この際、負極集電体に、表面にスラリーが塗布されていない部分を残した。 This slurry was applied to both surfaces of a negative electrode current collector, which was an aluminum foil having a thickness of 15 μm and an undercoat layer (carbon resin layer) having a thickness of 0.3 μm formed on both surfaces. At this time, a portion of the negative electrode current collector where the slurry was not applied was left on the surface.
　塗布したスラリーを乾燥させて、プレスし、片面あたりの厚さが２０μｍ、電極密度２．０ｇ／ｃｍ３の負極合剤層を負極集電体上に形成した。この時の塗工速度、乾燥温度、およびプレス温度は、表３に示す条件にて行った。次に、負極集電体において負極合剤層が表面に形成されていない部分を帯状に打ち抜き、負極集電タブを形成した。このようにして負極を作製した。 The applied slurry was dried and pressed to form a negative electrode mixture layer having a thickness of 20 μm on one side and an electrode density of 2.0 g / cm 3 on the negative electrode current collector. The coating speed, drying temperature, and press temperature at this time were performed under the conditions shown in Table 3. Next, a portion of the negative electrode current collector where the negative electrode mixture layer was not formed on the surface was punched into a band shape to form a negative electrode current collector tab. In this way, a negative electrode was produced.
　この負極を用いたことを除き、実施例１０と同様にして設計容量１Ａｈの非水電解質二次電池を作製した。これを実施例１２の二次電池とした。 A nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 10 except that this negative electrode was used. This was the secondary battery of Example 12.
　（実施例１３）
　実施例１における負極の作製と同様にしてスラリーを調整した。また、実施例１の負極に用いたと同様の負極集電体を準備した。このスラリーを負極集電体の両面に塗布する際に、塗工速度を１．０ｍ／分の速度としたこと以外は、実施例１と同様にして負極を作製した。 (Example 13)
A slurry was prepared in the same manner as in the preparation of the negative electrode in Example 1. Also, a negative electrode current collector similar to that used for the negative electrode of Example 1 was prepared. A negative electrode was produced in the same manner as in Example 1, except that the coating speed was 1.0 m / min when this slurry was applied to both surfaces of the negative electrode current collector.
　正極活物質として、中心粒子径９μｍのリン酸マンガン鉄リチウム（ＬｉＭｎ０．８Ｆｅ０．２ＰＯ４）粒子を用意した。このリン酸マンガン鉄リチウムを９０重量％、導電剤としてのアセチレンブラック及び黒鉛粉末を、それぞれ３重量％と２重量％、結着剤としてのポリアクリロニトリルを５重量％配合してＮ－メチルピロリドン（ＮＭＰ）溶媒に分散してスラリーを調整した。アルミニウム箔である厚さ１５μｍの正極集電体の両面にスラリーを塗布した。この際、正極集電体に、表面にスラリーが塗布されていない部分を残した。 As the positive electrode active material, lithium manganese iron phosphate (LiMn 0.8 Fe 0.2 PO 4 ) particles having a center particle diameter of 9 μm were prepared. N-methylpyrrolidone (90% by weight of lithium iron manganese phosphate, 3% by weight and 2% by weight of acetylene black and graphite powder as a conductive agent, and 5% by weight of polyacrylonitrile as a binder, respectively) NMP) was dispersed in a solvent to prepare a slurry. The slurry was applied to both surfaces of a positive electrode current collector having a thickness of 15 μm, which was an aluminum foil. At this time, a portion where the slurry was not applied on the surface was left on the positive electrode current collector.
　塗布したスラリーを乾燥させて、プレスし、電極密度が２．０ｇ／ｃｍ３の正極合剤層を正極集電体上に形成した。正極の重量は負極重量の１．１倍となるように調整した。次に、正極集電体において、正極合剤層が表面に形成されていない部分を帯状に打ち抜き、正極集電タブを形成した。こうして正極を作製した。 The applied slurry was dried and pressed to form a positive electrode mixture layer having an electrode density of 2.0 g / cm 3 on the positive electrode current collector. The weight of the positive electrode was adjusted to be 1.1 times the weight of the negative electrode. Next, in the positive electrode current collector, a portion where the positive electrode mixture layer was not formed on the surface was punched into a band shape to form a positive electrode current collector tab. In this way, a positive electrode was produced.
　この負極と正極とを用いたことを除き、実施例１と同様にして設計容量１Ａｈの非水電解質二次電池を作製した。これを実施例１３の二次電池とした。 A nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 1 except that this negative electrode and positive electrode were used. This was the secondary battery of Example 13.
　＜比較例１～比較例１１＞
　下記比較例１～１１において、負極の作製において用いた負極活物質および結着剤種、並びに正極の作製において用いた正極活物質を表４にまとめる。表５には、負極集電体におけるアンダーコート層の有無およびその厚さをまとめる。また、比較例１～１１における負極作製の条件（スラリーの塗工速度、スラリーの乾燥温度、プレス温度）を表６にまとめる。表６は、後述するように求められた、比較例１～１１についての負極集電体と負極合剤層との剥離強度α、負極合剤層における切削強度β、およびこれらの比（α／β）の値をさらに示す。 <Comparative Examples 1 to 11>
In Comparative Examples 1 to 11 below, Table 4 summarizes the negative electrode active material and the binder type used in the production of the negative electrode, and the positive electrode active material used in the production of the positive electrode. Table 5 summarizes the presence and thickness of the undercoat layer in the negative electrode current collector. In addition, Table 6 summarizes the negative electrode production conditions (slurry coating speed, slurry drying temperature, press temperature) in Comparative Examples 1 to 11. Table 6 shows the peel strength α between the negative electrode current collector and the negative electrode mixture layer, the cutting strength β in the negative electrode mixture layer, and the ratio (α / The value of β) is further shown.
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000006
　（比較例１）
　負極活物質として、実施例１で使用したものと同じチタン酸リチウム（Ｌｉ４Ｔｉ５Ｏ１２）粒子を用意した。このチタン酸リチウムを９０重量％、導電剤としてのアセチレンブラックを５重量％、結着剤としてのポリフッ化ビニリデン(ＰＶｄＦ)（株式会社クレハ製ＫＦ＃１７００）を５重量％配合し、Ｎ－メチルピロリドン(ＮＭＰ)溶媒に分散してスラリーを調整した。 (Comparative Example 1)
As the negative electrode active material, the same lithium titanate (Li 4 Ti 5 O 12 ) particles as those used in Example 1 were prepared. 90% by weight of this lithium titanate, 5% by weight of acetylene black as a conductive agent, 5% by weight of polyvinylidene fluoride (PVdF) (Kureha Co., Ltd. KF # 1700) as a binder, and N-methyl A slurry was prepared by dispersing in a pyrrolidone (NMP) solvent.
　このスラリーを、厚さ１５μｍで、その表面に厚さ１μｍのアンダーコート層（炭素樹脂層）が両面に形成されたアルミニウム箔である負極集電体の両面に塗布した。この際、負極集電体に、表面にスラリーが塗布されていない部分を残した。 The slurry was applied to both sides of a negative electrode current collector, which was an aluminum foil having a thickness of 15 μm and an undercoat layer (carbon resin layer) having a thickness of 1 μm formed on both surfaces. At this time, a portion of the negative electrode current collector where the slurry was not applied was left on the surface.
　塗布したスラリーを乾燥させて、プレスし、片面あたりの厚さが２０μｍ、電極密度２．０ｇ／ｃｍ３の負極合剤層を負極集電体上に形成した。この時の塗工速度、乾燥温度、およびプレス温度は、表６に示す条件にて行った。次に、負極集電体において負極合剤層が表面に形成されていない部分を帯状に打ち抜き、負極集電タブを形成した。このようにして負極を作製した。 The applied slurry was dried and pressed to form a negative electrode mixture layer having a thickness of 20 μm on one side and an electrode density of 2.0 g / cm 3 on the negative electrode current collector. The coating speed, drying temperature, and press temperature at this time were performed under the conditions shown in Table 6. Next, a portion of the negative electrode current collector where the negative electrode mixture layer was not formed on the surface was punched into a band shape to form a negative electrode current collector tab. In this way, a negative electrode was produced.
　この負極を用いたことを除き、実施例１と同様にして設計容量１Ａｈの非水電解質二次電池を作製した。これを比較例１の二次電池とした。 A nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 1 except that this negative electrode was used. This was designated as the secondary battery of Comparative Example 1.
　（比較例２）
負極活物質として、実施例１で使用したものと同じチタン酸リチウム（Ｌｉ４Ｔｉ５Ｏ１２）粒子を用意した。このチタン酸リチウムを９０重量％、導電剤としてのアセチレンブラックを７重量％、結着剤としてのポリフッ化ビニリデン(ＰＶｄＦ)（株式会社クレハ製ＫＦ＃１７００）を３重量％配合し、Ｎ－メチルピロリドン(ＮＭＰ)溶媒に分散してスラリーを調整した。 (Comparative Example 2)
As the negative electrode active material, the same lithium titanate (Li 4 Ti 5 O 12 ) particles as those used in Example 1 were prepared. 90% by weight of this lithium titanate, 7% by weight of acetylene black as a conductive agent, 3% by weight of polyvinylidene fluoride (PVdF) (Kureha KF # 1700) as a binder, and N-methyl A slurry was prepared by dispersing in a pyrrolidone (NMP) solvent.
　このスラリーを、アルミニウム箔である厚さ１５μｍの負極集電体（アンダーコート層無し）の両面に塗布した。この際、負極集電体に、表面にスラリーが塗布されていない部分を残した。 The slurry was applied to both sides of a 15 μm-thick negative electrode current collector (without an undercoat layer), which was an aluminum foil. At this time, a portion of the negative electrode current collector where the slurry was not applied was left on the surface.
　塗布したスラリーを乾燥させて、プレスし、片面あたりの厚さが２０μｍ、電極密度２．０ｇ／ｃｍ３の負極合剤層を負極集電体上に形成した。この時の塗工速度、乾燥温度、およびプレス温度は、表６に示す条件にて行った。次に、負極集電体において負極合剤層が表面に形成されていない部分を帯状に打ち抜き、負極集電タブを形成した。このようにして負極を作製した。 The applied slurry was dried and pressed to form a negative electrode mixture layer having a thickness of 20 μm on one side and an electrode density of 2.0 g / cm 3 on the negative electrode current collector. The coating speed, drying temperature, and press temperature at this time were performed under the conditions shown in Table 6. Next, a portion of the negative electrode current collector where the negative electrode mixture layer was not formed on the surface was punched into a band shape to form a negative electrode current collector tab. In this way, a negative electrode was produced.
　この負極を用いたことを除き、実施例１と同様にして設計容量１Ａｈの非水電解質二次電池を作製した。これを比較例２の二次電池とした。 A nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 1 except that this negative electrode was used. This was designated as the secondary battery of Comparative Example 2.
　（比較例３）
　負極活物質として、実施例１で使用したものと同じチタン酸リチウム（Ｌｉ４Ｔｉ５Ｏ１２）粒子を用意した。このチタン酸リチウムを９０重量％、導電剤としてのアセチレンブラックを７重量％、結着剤としてのポリアクリル酸（平均分子量４５万）を３重量％配合し、Ｎ－メチルピロリドン(ＮＭＰ)溶媒に分散してスラリーを調整した。 (Comparative Example 3)
As the negative electrode active material, the same lithium titanate (Li 4 Ti 5 O 12 ) particles as those used in Example 1 were prepared. 90% by weight of this lithium titanate, 7% by weight of acetylene black as a conductive agent, and 3% by weight of polyacrylic acid (average molecular weight 450,000) as a binder were blended into an N-methylpyrrolidone (NMP) solvent. The slurry was prepared by dispersing.
　このスラリーを、アルミニウム箔である厚さ１５μｍの負極集電体（アンダーコート層無し）の両面に塗布した。この際、負極集電体に、表面にスラリーが塗布されていない部分を残した。 The slurry was applied to both sides of a 15 μm-thick negative electrode current collector (without an undercoat layer), which was an aluminum foil. At this time, a portion of the negative electrode current collector where the slurry was not applied was left on the surface.
　塗布したスラリーを乾燥させて、プレスし、片面あたりの厚さが２０μｍ、電極密度２．０ｇ／ｃｍ３の負極合剤層を負極集電体上に形成した。この時の塗工速度、乾燥温度、およびプレス温度は、表６に示す条件にて行った。次に、負極集電体において負極合剤層が表面に形成されていない部分を帯状に打ち抜き、負極集電タブを形成した。このようにして負極を作製した。 The applied slurry was dried and pressed to form a negative electrode mixture layer having a thickness of 20 μm on one side and an electrode density of 2.0 g / cm 3 on the negative electrode current collector. The coating speed, drying temperature, and press temperature at this time were performed under the conditions shown in Table 6. Next, a portion of the negative electrode current collector where the negative electrode mixture layer was not formed on the surface was punched into a band shape to form a negative electrode current collector tab. In this way, a negative electrode was produced.
　この負極を用いたことを除き、実施例１と同様にして設計容量１Ａｈの非水電解質二次電池を作製した。これを比較例３の二次電池とした。 A nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 1 except that this negative electrode was used. This was designated as the secondary battery of Comparative Example 3.
　（比較例４）
　負極活物質として、実施例１で使用したものと同じチタン酸リチウム（Ｌｉ４Ｔｉ５Ｏ１２）粒子を用意した。このチタン酸リチウムを９０重量％、導電剤としてのアセチレンブラックを５重量％、結着剤としてのポリアクリロニトリルを５重量％配合し、Ｎ－メチルピロリドン（ＮＭＰ）溶媒に分散してスラリーを調整した。 (Comparative Example 4)
As the negative electrode active material, the same lithium titanate (Li 4 Ti 5 O 12 ) particles as those used in Example 1 were prepared. 90% by weight of this lithium titanate, 5% by weight of acetylene black as a conductive agent, and 5% by weight of polyacrylonitrile as a binder were mixed and dispersed in an N-methylpyrrolidone (NMP) solvent to prepare a slurry. .
　このスラリーを、アルミニウム箔である厚さ１５μｍの負極集電体（アンダーコート層無し）の両面に塗布した。この際、負極集電体に、表面にスラリーが塗布されていない部分を残した。 The slurry was applied to both sides of a 15 μm-thick negative electrode current collector (without an undercoat layer), which was an aluminum foil. At this time, a portion of the negative electrode current collector where the slurry was not applied was left on the surface.
　塗布したスラリーを乾燥させて、プレスし、片面あたりの厚さが２０μｍ、電極密度２．０ｇ／ｃｍ３の負極合剤層を負極集電体上に形成した。この時の塗工速度、乾燥温度、およびプレス温度は、表６に示す条件にて行った。次に、負極集電体において負極合剤層が表面に形成されていない部分を帯状に打ち抜き、負極集電タブを形成した。このようにして負極を作製した。 The applied slurry was dried and pressed to form a negative electrode mixture layer having a thickness of 20 μm on one side and an electrode density of 2.0 g / cm 3 on the negative electrode current collector. The coating speed, drying temperature, and press temperature at this time were performed under the conditions shown in Table 6. Next, a portion of the negative electrode current collector where the negative electrode mixture layer was not formed on the surface was punched into a band shape to form a negative electrode current collector tab. In this way, a negative electrode was produced.
　この負極を用いたことを除き、実施例１と同様にして設計容量１Ａｈの非水電解質二次電池を作製した。これを比較例４の二次電池とした。 A nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 1 except that this negative electrode was used. This was designated as the secondary battery of Comparative Example 4.
　（比較例５）
　負極活物質として、実施例１で使用したものと同じチタン酸リチウム（Ｌｉ４Ｔｉ５Ｏ１２）粒子を用意した。このチタン酸リチウムを９０重量％、導電剤としてのアセチレンブラックを７重量％、結着剤としてのポリアクリロニトリルを３重量％配合し、Ｎ－メチルピロリドン(ＮＭＰ)溶媒に分散してスラリーを調整した。 (Comparative Example 5)
As the negative electrode active material, the same lithium titanate (Li 4 Ti 5 O 12 ) particles as those used in Example 1 were prepared. 90% by weight of this lithium titanate, 7% by weight of acetylene black as a conductive agent and 3% by weight of polyacrylonitrile as a binder were blended and dispersed in an N-methylpyrrolidone (NMP) solvent to prepare a slurry. .
　このスラリーを、アルミニウム箔である厚さ１５μｍの負極集電体（アンダーコート層無し）の表面に塗布しようした。しかし、スラリーに対する負極集電体の濡れ性が悪く、ハジキ現象が生じてしまい、均一な負極を作製することができなかった。 This slurry was applied to the surface of a 15 μm-thick negative electrode current collector (no undercoat layer), which was an aluminum foil. However, the wettability of the negative electrode current collector with respect to the slurry was poor, and a repellency phenomenon occurred, and a uniform negative electrode could not be produced.
　このため、比較例５では、非水電解質二次電池を作製するに至らなかった。 For this reason, in Comparative Example 5, a non-aqueous electrolyte secondary battery could not be produced.
　（比較例６）
　負極活物質として、実施例１で使用したものと同じチタン酸リチウム（Ｌｉ４Ｔｉ５Ｏ１２）粒子を用意した。このチタン酸リチウムを９０重量％、導電剤としてのアセチレンブラックを３重量％、結着剤としてのポリアクリロニトリルを７重量％配合し、Ｎ－メチルピロリドン(ＮＭＰ)溶媒に分散してスラリーを調整した。 (Comparative Example 6)
As the negative electrode active material, the same lithium titanate (Li 4 Ti 5 O 12 ) particles as those used in Example 1 were prepared. 90% by weight of this lithium titanate, 3% by weight of acetylene black as a conductive agent and 7% by weight of polyacrylonitrile as a binder were blended and dispersed in an N-methylpyrrolidone (NMP) solvent to prepare a slurry. .
　このスラリーを、厚さ１５μｍで、その表面に厚さ０．３μｍのアンダーコート層（炭素樹脂層）が両面に形成されたアルミニウム箔である負極集電体の両面に塗布した。この際、負極集電体に、表面にスラリーが塗布されていない部分を残した。 This slurry was applied to both surfaces of a negative electrode current collector, which was an aluminum foil having a thickness of 15 μm and an undercoat layer (carbon resin layer) having a thickness of 0.3 μm formed on both surfaces. At this time, a portion of the negative electrode current collector where the slurry was not applied was left on the surface.
　塗布したスラリーを乾燥させて、プレスし、片面あたりの厚さが２０μｍ、電極密度２．０ｇ／ｃｍ３の負極合剤層を負極集電体上に形成した。この時の塗工速度、乾燥温度、およびプレス温度は、表６に示す条件にて行った。次に、負極集電体において負極合剤層が表面に形成されていない部分を帯状に打ち抜き、負極集電タブを形成した。このようにして負極を作製した。 The applied slurry was dried and pressed to form a negative electrode mixture layer having a thickness of 20 μm on one side and an electrode density of 2.0 g / cm 3 on the negative electrode current collector. The coating speed, drying temperature, and press temperature at this time were performed under the conditions shown in Table 6. Next, a portion of the negative electrode current collector where the negative electrode mixture layer was not formed on the surface was punched into a band shape to form a negative electrode current collector tab. In this way, a negative electrode was produced.
　この負極を用いたことを除き、実施例１と同様にして設計容量１Ａｈの非水電解質二次電池を作製した。これを比較例６の二次電池とした。 A nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 1 except that this negative electrode was used. This was designated as the secondary battery of Comparative Example 6.
　（比較例７）
　負極活物質として、実施例１で使用したものと同じチタン酸リチウム（Ｌｉ４Ｔｉ５Ｏ１２）粒子を用意した。このチタン酸リチウムを９０重量％、導電剤としてのアセチレンブラックを５重量％、結着剤としてのポリアクリル酸（平均分子量３００万）を５重量％配合し、Ｎ－メチルピロリドン(ＮＭＰ)溶媒に分散してスラリーを調整した。 (Comparative Example 7)
As the negative electrode active material, the same lithium titanate (Li 4 Ti 5 O 12 ) particles as those used in Example 1 were prepared. 90% by weight of this lithium titanate, 5% by weight of acetylene black as a conductive agent, and 5% by weight of polyacrylic acid (average molecular weight of 3 million) as a binder were blended into an N-methylpyrrolidone (NMP) solvent. The slurry was prepared by dispersing.
　このスラリーを、アルミニウム箔である厚さ１５μｍの負極集電体（アンダーコート層無し）の両面に塗布した。この際、負極集電体に、表面にスラリーが塗布されていない部分を残した。 The slurry was applied to both sides of a 15 μm-thick negative electrode current collector (without an undercoat layer), which was an aluminum foil. At this time, a portion of the negative electrode current collector where the slurry was not applied was left on the surface.
　塗布したスラリーを乾燥させて、プレスし、片面あたりの厚さが２０μｍ、電極密度２．０ｇ／ｃｍ３の負極合剤層を負極集電体上に形成した。この時の塗工速度、乾燥温度、およびプレス温度は、表６に示す条件にて行った。次に、負極集電体において負極合剤層が表面に形成されていない部分を帯状に打ち抜き、負極集電タブを形成した。このようにして負極を作製した。 The applied slurry was dried and pressed to form a negative electrode mixture layer having a thickness of 20 μm on one side and an electrode density of 2.0 g / cm 3 on the negative electrode current collector. The coating speed, drying temperature, and press temperature at this time were performed under the conditions shown in Table 6. Next, a portion of the negative electrode current collector where the negative electrode mixture layer was not formed on the surface was punched into a band shape to form a negative electrode current collector tab. In this way, a negative electrode was produced.
　この負極を用いたことを除き、実施例１と同様にして設計容量１Ａｈの非水電解質二次電池を作製した。これを比較例７の二次電池とした。 A nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 1 except that this negative electrode was used. This was designated as the secondary battery of Comparative Example 7.
　（比較例８）
　負極活物質として、実施例１０で使用したものと同じ単斜晶型チタン複合酸化物(ＴｉＯ２)を用意した。このチタン複合酸化物を９０重量％、導電剤としてのアセチレンブラックを６重量％、結着剤として高分子タイプのポリフッ化ビニリデン(ＰＶｄＦ)（株式会社クレハ製ＫＦ＃７３００）を４重量％配合し、Ｎ－メチルピロリドン(ＮＭＰ)溶媒に分散してスラリーを調整した。 (Comparative Example 8)
As the negative electrode active material, the same monoclinic titanium composite oxide (TiO 2 ) as used in Example 10 was prepared. 90% by weight of this titanium composite oxide, 6% by weight of acetylene black as a conductive agent, and 4% by weight of polymer type polyvinylidene fluoride (PVdF) (Kureha Corporation KF # 7300) as a binder. The slurry was prepared by dispersing in N-methylpyrrolidone (NMP) solvent.
　このスラリーを、実施例１０と同様に、厚さ１５μｍで、その表面に厚さ０．３μｍのアンダーコート層（炭素樹脂層）が両面に形成されたアルミニウム箔である負極集電体の両面に塗布した。 Similar to Example 10, this slurry was applied to both surfaces of a negative electrode current collector, which is an aluminum foil having a thickness of 15 μm and an undercoat layer (carbon resin layer) having a thickness of 0.3 μm formed on both surfaces. Applied.
　塗布したスラリーを乾燥させ、プレスして、片面あたりの厚さが１９μｍ、電極密度２．０ｇ／ｃｍ３の負極合剤層を負極集電体上に形成した。この時の塗工速度、乾燥温度、およびプレス温度は、表６に示す条件にて行った。次に、負極集電体において負極合剤層が表面に形成されていない部分を帯状に打ち抜き、負極集電タブを形成した。このようにして負極を作製した。 The applied slurry was dried and pressed to form a negative electrode mixture layer having a thickness of 19 μm on one side and an electrode density of 2.0 g / cm 3 on the negative electrode current collector. The coating speed, drying temperature, and press temperature at this time were performed under the conditions shown in Table 6. Next, a portion of the negative electrode current collector where the negative electrode mixture layer was not formed on the surface was punched into a band shape to form a negative electrode current collector tab. In this way, a negative electrode was produced.
　この負極を用いたことを除き、実施例１と同様にして設計容量１Ａｈの非水電解質二次電池を作製した。これを比較例８の二次電池とした。 A nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 1 except that this negative electrode was used. This was designated as the secondary battery of Comparative Example 8.
　（比較例９）
　負極活物質として、実施例１１で使用したものと同じニオブ含有チタン複合酸化物（ＴｉＮｂ２Ｏ７）を用意した。このニオブ含有チタン複合酸化物を９０重量％、導電剤としてのアセチレンブラックを６重量％、結着剤として高分子タイプのポリフッ化ビニリデン(ＰＶｄＦ)（株式会社クレハ製ＫＦ＃７３００）を４重量％配合し、Ｎ－メチルピロリドン(ＮＭＰ)溶媒に分散してスラリーを調整した。 (Comparative Example 9)
The same niobium-containing titanium composite oxide (TiNb 2 O 7 ) as that used in Example 11 was prepared as the negative electrode active material. 90% by weight of this niobium-containing titanium composite oxide, 6% by weight of acetylene black as a conductive agent, and 4% by weight of polymer-type polyvinylidene fluoride (PVdF) (Kureha KF # 7300) as a binder. A slurry was prepared by mixing and dispersing in an N-methylpyrrolidone (NMP) solvent.
　このスラリーを、実施例１１と同様に、厚さ１５μｍで、その表面に厚さ０．３μｍのアンダーコート層（炭素樹脂層）が両面に形成されたアルミニウム箔である負極集電体の両面に塗布した。 As in Example 11, this slurry was applied to both surfaces of a negative electrode current collector, which is an aluminum foil having a thickness of 15 μm and an undercoat layer (carbon resin layer) having a thickness of 0.3 μm formed on both surfaces. Applied.
　塗布したスラリーを乾燥させ、プレスして、片面あたりの厚さが１５μｍ、電極密度２．４ｇ／ｃｍ３の負極合剤層を負極集電体上に形成した。この時の塗工速度、乾燥温度、およびプレス温度は、表６に示す条件にて行った。次に、負極集電体において負極合剤層が表面に形成されていない部分を帯状に打ち抜き、負極集電タブを形成した。このようにして負極を作製した。 The applied slurry was dried and pressed to form a negative electrode mixture layer having a thickness of 15 μm on one side and an electrode density of 2.4 g / cm 3 on the negative electrode current collector. The coating speed, drying temperature, and press temperature at this time were performed under the conditions shown in Table 6. Next, a portion of the negative electrode current collector where the negative electrode mixture layer was not formed on the surface was punched into a band shape to form a negative electrode current collector tab. In this way, a negative electrode was produced.
　この負極を用いたことを除き、実施例１と同様にして設計容量１Ａｈの非水電解質二次電池を作製した。これを比較例９の二次電池とした。 A nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 1 except that this negative electrode was used. This was designated as the secondary battery of Comparative Example 9.
　（比較例１０）
　負極活物質として、実施例１２で使用したものと同じナトリウム含有チタン複合酸化物（Ｌｉ２Ｎａ２Ｔｉ６Ｏ１４）を用意した。このナトリウム含有チタン複合酸化物を９０重量％、導電剤としてのアセチレンブラックを６重量％、結着剤として高分子タイプのポリフッ化ビニリデン(ＰＶｄＦ)（株式会社クレハ製ＫＦ＃７３００）を４重量％配合し、Ｎ－メチルピロリドン(ＮＭＰ)溶媒に分散してスラリーを調整した。 (Comparative Example 10)
The same sodium-containing titanium composite oxide (Li 2 Na 2 Ti 6 O 14 ) as that used in Example 12 was prepared as the negative electrode active material. 90% by weight of this sodium-containing titanium composite oxide, 6% by weight of acetylene black as a conductive agent, and 4% by weight of polymer type polyvinylidene fluoride (PVdF) (KF # 7300 manufactured by Kureha Corporation) as a binder. A slurry was prepared by mixing and dispersing in an N-methylpyrrolidone (NMP) solvent.
　このスラリーを、実施例１２と同様に、厚さ１５μｍで、その表面に厚さ０．３μｍのアンダーコート層（炭素樹脂層）が両面に形成されたアルミニウム箔である負極集電体の両面に塗布した。 Similar to Example 12, this slurry was applied to both surfaces of a negative electrode current collector, which is an aluminum foil having a thickness of 15 μm and an undercoat layer (carbon resin layer) having a thickness of 0.3 μm formed on both surfaces. Applied.
　塗布したスラリーを乾燥させ、プレスして、片面あたりの厚さが２０μｍ、電極密度２．０ｇ／ｃｍ３の負極合剤層を負極集電体上に形成した。この時の塗工速度、乾燥温度、およびプレス温度は、表６に示す条件にて行った。 The applied slurry was dried and pressed to form a negative electrode mixture layer having a thickness of 20 μm on one side and an electrode density of 2.0 g / cm 3 on the negative electrode current collector. The coating speed, drying temperature, and press temperature at this time were performed under the conditions shown in Table 6.
　この負極を用いたことを除き、実施例１と同様にして設計容量１Ａｈの非水電解質二次電池を作製した。これを比較例１０の二次電池とした。 A nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 1 except that this negative electrode was used. This was designated as the secondary battery of Comparative Example 10.
　（比較例１１）
　負極活物質として、平均粒径１０μｍの黒鉛粉末（メソフェーズ小球体）を用意した。この黒鉛粉末を９５重量％、結着剤としてのポリアクリル酸（平均分子量４５万）を５重量％配合し、Ｎ－メチルピロリドン(ＮＭＰ)を固形分比が７０重量％になるように添加した。これをプラネタリ―ミキサ（プライミクス株式会社製　ハイビスディスパ―ミックス　３Ｄ－０５）で混練し、ＮＭＰを加えながら固形分比を徐々に低下させてスラリーを調整した。 (Comparative Example 11)
As a negative electrode active material, graphite powder (mesophase spherules) having an average particle size of 10 μm was prepared. This graphite powder was mixed at 95% by weight, 5% by weight of polyacrylic acid (average molecular weight 450,000) as a binder, and N-methylpyrrolidone (NMP) was added to a solid content ratio of 70% by weight. . This was kneaded with a planetary mixer (Hibis Disperse Mix 3D-05 manufactured by PRIMIX Corporation), and the slurry was adjusted by gradually reducing the solid content ratio while adding NMP.
　このスラリーを、連続式ビーズミル（アイメックス株式会社製　ＲＭＨ－０３）を用い、回転数１５００ｒｐｍ、流量３０ｃｃ／分の条件で湿式粉砕・分散処理し、スラリーを調整した。 The slurry was wet pulverized and dispersed using a continuous bead mill (RMH-03, manufactured by IMEX Co., Ltd.) under the conditions of a rotational speed of 1500 rpm and a flow rate of 30 cc / min to prepare a slurry.
　続いて、このスラリーを、厚さが１５μｍで、その表面に厚さ０．３μｍのアンダーコート層（炭素樹脂層）が両面に形成された銅箔である負極集電体の両面に、スロットダイ式塗工装置（株式会社廉井精機製）により塗工速度１ｍ／分の速度で塗布し、乾燥温度１４０℃で乾燥させた。 Subsequently, the slurry was applied to both sides of a negative electrode current collector, which is a copper foil having a thickness of 15 μm and an undercoat layer (carbon resin layer) having a thickness of 0.3 μm formed on both surfaces. The coating was applied at a coating speed of 1 m / min with a coater (manufactured by Yasui Seiki Co., Ltd.) and dried at a drying temperature of 140 ° C.
　更に、得られた塗布電極を、ロールプレス装置（大野ロール製）によりプレス温度８０℃でプレスを行い、片面あたりの厚さが３０μｍ、電極密度１．４ｇ／ｃｍ３の負極合剤層を負極集電体上に形成した。次に、負極集電体において負極合剤層が表面に形成されていない部分を帯状に打ち抜き、負極集電タブを形成した。このようにして負極を作製した。 Furthermore, the obtained coated electrode was pressed at a press temperature of 80 ° C. by a roll press apparatus (manufactured by Ohno Roll), and a negative electrode mixture layer having a thickness of 30 μm per side and an electrode density of 1.4 g / cm 3 was formed as a negative electrode. Formed on the current collector. Next, a portion of the negative electrode current collector where the negative electrode mixture layer was not formed on the surface was punched into a band shape to form a negative electrode current collector tab. In this way, a negative electrode was produced.
　比較例１１では、液状非水電解質を次のようにして調製した。エチレンカーボネート（ＥＣ）およびジエチルカーボネート（ＤＥＣ）を１：１の体積比率で混合して混合溶媒とした。この混合溶媒に電解質であるＬｉＰＦ６を１．５ｍｏｌ／Ｌ溶解させ、液状非水電解質を調製した。 In Comparative Example 11, a liquid nonaqueous electrolyte was prepared as follows. Ethylene carbonate (EC) and diethyl carbonate (DEC) were mixed at a volume ratio of 1: 1 to obtain a mixed solvent. LiPF 6 which is an electrolyte was dissolved in this mixed solvent at 1.5 mol / L to prepare a liquid non-aqueous electrolyte.
　上記のようにして得られた負極と液状非水電解質とを用いたことを除き、実施例１と同様にして設計容量１Ａｈの非水電解質二次電池を作製した。これを比較例１１の二次電池とした。 A nonaqueous electrolyte secondary battery having a design capacity of 1 Ah was produced in the same manner as in Example 1 except that the negative electrode obtained as described above and a liquid nonaqueous electrolyte were used. This was designated as the secondary battery of Comparative Example 11.
　実施例１において作製した負極に対し、上述したとおりにＳＥＭ測定を行った際の断面ＳＥＭ像を図７に示す。上述したとおり、実施例１では、負極集電体として、その表面に厚さ１μｍのアンダーコート層が形成されたアルミニウム箔を用いた。実施例１で作製した負極では、図７に示すように、アルミニウム箔（負極集電体３ａ）と負極合剤層３ｂとの間にアンダーコート層３ｃが配置されている。 FIG. 7 shows a cross-sectional SEM image when the SEM measurement was performed on the negative electrode produced in Example 1 as described above. As described above, in Example 1, as the negative electrode current collector, an aluminum foil having an undercoat layer having a thickness of 1 μm formed on the surface thereof was used. In the negative electrode produced in Example 1, as shown in FIG. 7, the undercoat layer 3c is disposed between the aluminum foil (negative electrode current collector 3a) and the negative electrode mixture layer 3b.
　図８に、比較例４において作製した負極の断面ＳＥＭ像を示す。上述したとおり、比較例４では、負極集電体として、アンダーコート層を有さないアルミニウム箔を用いた。比較例４で作製した負極では、図８に示す様に、アルミニウム箔（負極集電体３ａ）の表面に負極合剤層３ｂが直接形成されている。 FIG. 8 shows a cross-sectional SEM image of the negative electrode produced in Comparative Example 4. As described above, in Comparative Example 4, an aluminum foil having no undercoat layer was used as the negative electrode current collector. In the negative electrode prepared in Comparative Example 4, as shown in FIG. 8, the negative electrode mixture layer 3b is directly formed on the surface of the aluminum foil (negative electrode current collector 3a).
　＜初回容量測定＞
　次に、実施例１～１３および比較例１～４、６～１１の二次電池について、初回容量測定を行った。初回容量測定は以下の手順で行った。 <Initial volume measurement>
Next, for the secondary batteries of Examples 1 to 13 and Comparative Examples 1 to 4 and 6 to 11, initial capacity measurement was performed. The initial volume measurement was performed according to the following procedure.
　まず、実施例１～９並びに実施例１３、および比較例１～４並びに比較例６～７の二次電池は、２５℃の温度条件の下、１Ａ（１Ｃ）の定電流で２．７Ｖまで充電した後、定電圧で充電する定電流－定電圧充電を行った。なお、この状態をＳＯＣ１００％とした。その後、１Ａ（１Ｃ）の電流値で１．５Ｖまで放電した時の容量を測定した。 First, the secondary batteries of Examples 1 to 9, and Example 13, and Comparative Examples 1 to 4 and Comparative Examples 6 to 7 are up to 2.7 V at a constant current of 1 A (1 C) under a temperature condition of 25 ° C. After charging, constant current-constant voltage charging, in which charging was performed at a constant voltage, was performed. This state was set to SOC 100%. Then, the capacity | capacitance when discharged to 1.5V with the electric current value of 1A (1C) was measured.
　一方、実施例１０～１１および比較例８～９の二次電池は、２５℃の温度条件の下、１Ａ（１Ｃ）の定電流で２．８Ｖまで充電した後、定電圧で充電する定電流－定電圧充電を行った。なお、この状態をＳＯＣ１００％とした。その後、１Ａ（１Ｃ）の電流値で１．５Ｖまで放電した時の容量を測定した。 On the other hand, the secondary batteries of Examples 10 to 11 and Comparative Examples 8 to 9 were charged at a constant voltage after being charged to 2.8 V with a constant current of 1 A (1 C) under a temperature condition of 25 ° C. -A constant voltage charge was performed. This state was set to SOC 100%. Then, the capacity | capacitance when discharged to 1.5V with the electric current value of 1A (1C) was measured.
　また、実施例１０、比較例８の二次電池については、２５℃の温度条件下、１Ａ（１Ｃ）の定電流で３．０Ｖまで充電した後、定電圧で充電する定電流－定電圧充電を行った。なお、この状態をＳＯＣ１００％とした。その後、１Ａ（１Ｃ）の電流値で１．５Ｖまで放電した時の容量を測定した。 In addition, for the secondary batteries of Example 10 and Comparative Example 8, constant current-constant voltage charging, in which charging is performed at a constant voltage after charging to 3.0 V at a constant current of 1 A (1 C) under a temperature condition of 25 ° C. Went. This state was set to SOC 100%. Then, the capacity | capacitance when discharged to 1.5V with the electric current value of 1A (1C) was measured.
　比較例１１の二次電池は、２５℃の温度条件下、１Ａ（１Ｃ）の定電流で４．２Ｖまで充電した後、定電圧で充電する定電流－定電圧充電を行った。なお、この状態をＳＯＣ１００％とした。その後、１Ａ（１Ｃ）の電流値で２．７５Ｖまで放電した時の容量を測定した。 The secondary battery of Comparative Example 11 was charged at a constant current of 1 A (1 C) to 4.2 V under a temperature condition of 25 ° C., and then was subjected to a constant current-constant voltage charge charged at a constant voltage. This state was set to SOC 100%. Then, the capacity | capacitance when discharged to 2.75V with the electric current value of 1A (1C) was measured.
　実施例１～１３および比較例１～４、６～９の二次電池について得られた初回放電容量測定の結果を、表７に示す。 Table 7 shows the results of the initial discharge capacity measurements obtained for the secondary batteries of Examples 1 to 13 and Comparative Examples 1 to 4 and 6 to 9.
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000007
　＜電池性能の評価＞
　次に、電池の出力性能を評価するために、実施例１～１３および比較例１～４、６～１１の二次電池のそれぞれについて、２５℃の温度条件の下で、充電率１００％（ＳＯＣ１００％）の状態から１Ａ（１Ｃ）及び３０Ａ（３０Ｃ）の電流値で連続放電する大電流放電試験を行った。それぞれの電流値で放電したときに得られた放電容量の比（Ｃ３０／Ｃ１）を大電流放電容量比として表７に示す。 <Evaluation of battery performance>
Next, in order to evaluate the output performance of the battery, each of the secondary batteries of Examples 1 to 13 and Comparative Examples 1 to 4 and 6 to 11 was charged at a charging rate of 100% under a temperature condition of 25 ° C. A large current discharge test was conducted in which discharge was continuously performed at a current value of 1A (1C) and 30A (30C) from the state of SOC 100%. The discharge capacity ratio (C 30 / C 1 ) obtained when discharging at each current value is shown in Table 7 as the large current discharge capacity ratio.
　次に、高温耐久性について評価するために、実施例１～１３および比較例１～４、６～１１の二次電池のそれぞれについて、８０℃の温度条件下でサイクル試験を行い、サイクル寿命と抵抗増加率を求めた。 Next, in order to evaluate the high-temperature durability, each of the secondary batteries of Examples 1 to 13 and Comparative Examples 1 to 4 and 6 to 11 was subjected to a cycle test at a temperature of 80 ° C. The resistance increase rate was obtained.
　まず、２５℃において、それぞれの二次電池を充電率５０％（ＳＯＣ５０％）の状態から１Ｃ（１Ａ）及び１０Ｃ（１０Ａ）の電流値で放電し、放電１０秒後のセル電圧からセル抵抗値（Ｒ１）を算出した。 First, at 25 ° C., each secondary battery is discharged at a current value of 1C (1A) and 10C (10A) from a state where the charging rate is 50% (SOC 50%), and the cell resistance value is calculated from the cell voltage 10 seconds after the discharge. (R 1 ) was calculated.
　次に、８０℃において、５Ａ（５Ｃ）の電流値で充電し、５Ａ（５Ｃ）の電流値で放電する、５Ｃ/５Ｃサイクル試験を実施した。充電電圧、放電終止電圧等の条件は、初回容量測定と同条件にて行った。そして、放電容量が初回容量の８０％となったサイクル数を、高温（８０℃）におけるそれぞれの二次電池のサイクル寿命として表７に示す。 Next, a 5C / 5C cycle test was performed in which the battery was charged at a current value of 5A (5C) and discharged at a current value of 5A (5C) at 80 ° C. Conditions such as the charge voltage and the discharge end voltage were the same as those for the initial capacity measurement. The number of cycles at which the discharge capacity becomes 80% of the initial capacity is shown in Table 7 as the cycle life of each secondary battery at high temperature (80 ° C.).
　また、それぞれの二次電池について、５００サイクル経過時に、１サイクル後の抵抗値（Ｒ１）の測定と同様にして、５００サイクル後の抵抗値（Ｒ５００）を測定した。１サイクル後の抵抗値（Ｒ１）と５００サイクル後の抵抗値（Ｒ５００）とから、抵抗増加率（Ｒ５００／Ｒ１）を求めた。その結果を併せて表７に示す。 For each secondary battery, the resistance value (R 500 ) after 500 cycles was measured in the same manner as the measurement of the resistance value (R 1 ) after one cycle when 500 cycles had elapsed. From the resistance value (R 1 ) after one cycle and the resistance value (R 500 ) after 500 cycles, the rate of increase in resistance (R 500 / R 1 ) was determined. The results are also shown in Table 7.
　ただし、比較例１１の二次電池については、８０℃サイクル試験において、６０サイクル経過時点からセルの膨れが観測された。また、１００サイクル経過時点で抵抗増加率が１．５倍に達したことが観測されたため、そこで試験を中止した。 However, for the secondary battery of Comparative Example 11, in the 80 ° C. cycle test, cell swelling was observed from the time when 60 cycles had elapsed. Moreover, since it was observed that the rate of increase in resistance reached 1.5 times after 100 cycles, the test was stopped there.
　なお、実施例１～１３および比較例１～４、６～１１で作製した負極について、レオテック社製電極剥離強度測定装置(レオメーター)を用いて、先に詳細に説明したように剥離強度α（ピール強度）を測定した。ここで、負極集電体から負極合剤層を２ｃｍ剥離するのに必要とされた力（ｇｆ/２ｃｍ）を求め、これを単位換算して剥離強度α（Ｎ／ｍ）として記録した。また、それぞれの実施例および比較例について、負極を２０ｍｍ角に切り取り、切削強度用評価サンプルとした。切削強度測定装置サイカス（登録商標）ＤＮ－ＧＳ型（ダイプラ・ウインテス（株）製）を用いて、先に詳細に説明した表面・界面切削法により、評価用サンプルの負極合剤層における切削強度β（せん断力）を測定した。上述したとおり、得られた剥離強度αおよび切削強度β、並びにこれらの比（α／β）を表３、表６にまとめる。 For the negative electrodes prepared in Examples 1 to 13 and Comparative Examples 1 to 4 and 6 to 11, the peel strength α as described in detail above using an electrode peel strength measuring device (rheometer) manufactured by Rheotech Co., Ltd. (Peel strength) was measured. Here, the force (gf / 2 cm) required to peel the negative electrode mixture layer 2 cm from the negative electrode current collector was determined, and this was converted into a unit and recorded as the peel strength α (N / m). Moreover, about each Example and the comparative example, the negative electrode was cut off to 20 square mm and it was set as the evaluation sample for cutting strength. Using the cutting strength measuring device Cycus (registered trademark) DN-GS type (manufactured by Daipura Wintes Co., Ltd.), the cutting strength in the negative electrode mixture layer of the sample for evaluation by the surface / interface cutting method described in detail above β (shear force) was measured. As described above, the obtained peel strength α and cutting strength β and the ratio (α / β) are summarized in Tables 3 and 6.
　表７に示すように、実施例１～１３は、比較例１～４、６～１０に比べ、出力性能に優れ、かつサイクル寿命が長く、優れた高温耐久性を示すことができる。 As shown in Table 7, Examples 1 to 13 are superior to Comparative Examples 1 to 4 and 6 to 10 in terms of output performance, have a long cycle life, and can exhibit excellent high temperature durability.
　また、表７に示すように、実施例１～１３は、比較例１～４、６～１０に比べ、高温条件下での抵抗増加率が小さく、高温耐久性に優れることがわかる。 Also, as shown in Table 7, it can be seen that Examples 1 to 13 have a smaller resistance increase rate under high temperature conditions and excellent high temperature durability than Comparative Examples 1 to 4 and 6 to 10.
　なお、比較例１～２および比較例１０の二次電池は、出力性能には優れるものの、実施例１～１３の二次電池に比べ、サイクル寿命が短く、抵抗増加が大きいことがわかる。 Although the secondary batteries of Comparative Examples 1 and 2 and Comparative Example 10 are excellent in output performance, it can be seen that the cycle life is short and the resistance increase is large compared to the secondary batteries of Examples 1 to 13.
　以上説明した実施形態および実施例によれば、非水電解質二次電池が提供される。この非水電解質二次電池は、正極と、負極と、非水電解質とを含む。負極は、負極集電体と、この負極集電体上に配置されている負極合剤層とを含む。負極集電体は、金属箔を含んでいる。負極合剤層は、リチウムイオンを吸蔵および放出するチタン含有金属酸化物とアクリル系樹脂を含む結着剤とを含んでいる。負極集電体と負極合剤層との剥離強度α（Ｎ／ｍ）と、負極合剤層において表面・界面切削法により測定される切削強度β（Ｎ／ｍ）とは、α／β＞１．３６×１０－２の関係を満たす。この非水電解質二次電池は、出力性能に優れ、且つ高温耐久性に優れる。 According to the embodiments and examples described above, a non-aqueous electrolyte secondary battery is provided. This non-aqueous electrolyte secondary battery includes a positive electrode, a negative electrode, and a non-aqueous electrolyte. The negative electrode includes a negative electrode current collector and a negative electrode mixture layer disposed on the negative electrode current collector. The negative electrode current collector includes a metal foil. The negative electrode mixture layer contains a titanium-containing metal oxide that occludes and releases lithium ions and a binder containing an acrylic resin. The peel strength α (N / m) between the negative electrode current collector and the negative electrode mixture layer and the cutting strength β (N / m) measured by the surface / interface cutting method in the negative electrode mixture layer are α / β> The relationship of 1.36 × 10 −2 is satisfied. This non-aqueous electrolyte secondary battery is excellent in output performance and excellent in high temperature durability.
　以上、本発明の実施の形態を説明したが、本発明はこれらに限られず、請求の範囲に記載の発明の要旨の範疇において様々に変更可能である。また、本発明は、実施段階ではその要旨を逸脱しない範囲で種々に変形することが可能である。さらに、上記実施形態に開示されている複数の構成要素を適宜組み合わせることにより種々の発明を形成できる。 Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications can be made within the scope of the gist of the invention described in the claims. In addition, the present invention can be variously modified without departing from the scope of the invention in the implementation stage. Furthermore, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment.
　１，１１…電極群、２，１２…外装部材、３，１４…負極、４，１５…セパレータ、５，１３…正極、６，１６…負極端子、７，１７…正極端子、２１…単電池、２４…プリント配線基板、２５…サーミスタ、２６…保護回路、３７…収納容器。 DESCRIPTION OF SYMBOLS 1,11 ... Electrode group, 2,12 ... Exterior member, 3,14 ... Negative electrode, 4,15 ... Separator, 5,13 ... Positive electrode, 6,16 ... Negative electrode terminal, 7, 17 ... Positive electrode terminal, 21 ... Single cell 24 ... Printed circuit board, 25 ... Thermistor, 26 ... Protection circuit, 37 ... Storage container.

Claims (6)

  1. 　正極と、
    　負極集電体と前記負極集電体上に配置されている負極合剤層とを含み、前記負極合剤層はリチウムイオンを吸蔵および放出するチタン含有金属酸化物とアクリル系樹脂を含む結着剤とを含んでおり、下記式（Ｉ）を満たす負極と、
    　非水電解質とを具備する非水電解質二次電池。
    　　　α／β＞１．３６×１０－２　（Ｉ）
    ここで、αは前記負極集電体と前記負極合剤層との剥離強度（Ｎ／ｍ）であり、βは前記負極合剤層における表面・界面切削法により測定される切削強度（Ｎ／ｍ）である。     A positive electrode;
    A negative electrode current collector and a negative electrode mixture layer disposed on the negative electrode current collector, wherein the negative electrode mixture layer includes a titanium-containing metal oxide that absorbs and releases lithium ions and an acrylic resin. A negative electrode satisfying the following formula (I):
    A non-aqueous electrolyte secondary battery comprising a non-aqueous electrolyte.
    α / β> 1.36 × 10 −2 (I)
    Here, α is the peel strength (N / m) between the negative electrode current collector and the negative electrode mixture layer, and β is the cutting strength (N / M) measured by the surface / interface cutting method in the negative electrode mixture layer. m).
  2. 　前記負極は、さらに下記式（ＩＩ）を満たす請求項１に記載の非水電解質二次電池。
    　　　α／β＜４．９×１０－２　　（ＩＩ）
    ここで、αは前記負極集電体と前記負極合剤層との剥離強度（Ｎ／ｍ）であり、βは前記負極合剤層における表面・界面切削法により測定される切削強度（Ｎ／ｍ）である。     The non-aqueous electrolyte secondary battery according to claim 1, wherein the negative electrode further satisfies the following formula (II).
    α / β <4.9 × 10 −2 (II)
    Here, α is the peel strength (N / m) between the negative electrode current collector and the negative electrode mixture layer, and β is the cutting strength (N / M) measured by the surface / interface cutting method in the negative electrode mixture layer. m).
  3. 　前記負極集電体と前記負極合剤層との剥離強度αが、２．５Ｎ／ｍ以上２７Ｎ／ｍ以下である請求項１または２に記載の非水電解質二次電池。 The nonaqueous electrolyte secondary battery according to claim 1 or 2, wherein a peel strength α between the negative electrode current collector and the negative electrode mixture layer is 2.5 N / m or more and 27 N / m or less.
  4. 　前記アクリル系樹脂がニトリル基を含んでいる請求項１から請求項３のいずれか１項に記載の非水電解質二次電池。 The nonaqueous electrolyte secondary battery according to any one of claims 1 to 3, wherein the acrylic resin contains a nitrile group.
  5. 　請求項１から請求項４のいずれか１項に記載の非水電解質二次電池を複数具備し、前記複数の非水電解質二次電池が電気的に直列及び／又は並列に接続されている電池パック。 A battery comprising a plurality of the nonaqueous electrolyte secondary batteries according to any one of claims 1 to 4, wherein the plurality of nonaqueous electrolyte secondary batteries are electrically connected in series and / or in parallel. pack.
  6. 　エンジンルームに配置されている請求項５記載の電池パックを具備する自動車。 An automobile comprising the battery pack according to claim 5 disposed in an engine room.
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JPWO2017046896A1 (en) 2017-09-14
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JP6130052B1 (en) 2017-05-17

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